CNC Router Table, Step 8

CNCSo after picking all the moving parts designing your axis and making a very sturdy machine you need to compliment it with a very sturdy and well thought out cutting bed.

Get it right and it will make your CNC’ing experience enjoyable.

Most people that by second-hand machines overlook the cutting bed and always an underestimated part of the machine, when designing your machine it is important to understand what you will be using your machine for as there will be a bed style that fits your machine best.

For example, if you are making a bar length machine you will be better using a fixed clamping setup.

Or if you are building a machine for prototyping you will probably be working with materials of all shape and size, this would probably be best suited to a T-slot style bed, which offers many different clamping solutions, then again you may be making the same product over and over in that case you would get away with a flatbed with preconfigured holes for clamps, so their variety of different pieces or same product repeated.

On modern tables, you may find they have a combination of cutting beds while this is good its also a lot of work to get right and consumes a lot of space.

If you are designing and building your own CNC machine, your options are unlimited the only limit you have is your imagination and budget to contend with.

With that said we have 3 main cutting beds to cover for the DIY builder.


cncT-Slot Table


CNCThe Vacuum Table


CNCThe "Disposable" Table Top


CNC Motor Selection, Step 7.

CNCCNC motors are literally the heart of the CNC machine without them we would not be able to drive the axis back and forth and your spindle motor would just sit in one position.

The type and size will define the machines accuracy precision and speed.

There are two main types of CNC motors these are servo and stepper motors, and within these two motor types, there are 7 good options for a CNC build.

Both stepper and servo motors have advantages and disadvantages and selecting the right one to make your machine perform well and efficiently, picking the right one will be covered in the articles below.

In the following articles we will be covering aspects of all types of CNC motors, selecting the motors goes hand in hand with selecting the right CNC controller and selecting the right drive components that we covered in the last section.


cncTerminology linked to Motors


CNCStepper Motors Vs Servo Motors


stepperStepper Motors


servoServo Motor


CNC drive components, Step 6

What is CNC drive components?

CNCThe Components that make up the CNC’s drive are the ball screws, lead screws or rack and pinion, they are mechanical components that drive the axis back and forth on its linear rails, they achieve this by converting the rotating motion of the stepper or servo motor into a linear motion.

The idea of the drive components are really simple and when diy'er are choosing the drive system you really can't go wrong, but there are certain things to consider as all the different types have their pros and cons.

The drive system has a heavy impact on the CNC machines performance and capabilities, once you understand the CNC drive systems, you will have a better understanding on how your machine will perform and what its capabilities will be.

Just by changing a few components on your CNC will majorly impact the CNC machines precision and accuracy, the force that can be applied to the cutter and cutting speed of your machine.

If you are considering buying a CNC machine it would be a good idea to find out what drive system is installed on that machine, this will give you a good understanding of the capabilities and lifespan of the machine. This can be especially true when it comes to buying a second-hand machine.

Look into what components have installed the condition they are and if possible are replacements available if needed.

In this guide, you will find.


ACME Lead Screws

CNC


ACME Nuts


Ball Screw


Rack an Pinion


Pulleys and Timing Belts


DIY Drive System


Y-Axis Frame Design, Step 3

Since we have gained a full understanding of the X-axis frame designs, step2 concerning a DIY CNC router design, it is also necessary to consider the Y-axis assembly and design.

For those that enjoy DIY projects, the gantry design is quite common to people who are actively involved with CNC routers. This design finds a wide application because it is one that works the way it is intended. There are different designs which you can adapt and may be most suitable depending on the type of material available, the parts, and the limits of your budget.

Of all the “DIY CNC routers,” the gantry design has been determined to work best. Regardless of this, there are certain things you need to note about the design.

Stability and balance are two essential design features which your gantry should possess. Your CNC gantry should have a design that ensures it is able to withstand any force that will be acting on it. This protects the lead screw, bearings, and motor from encountering strain and stress which are in excess.

Defining the forces that will be acting on the gantry is the first step to take in order to come up with a gantry design that will be able to counter the forces.

Y-Axis

To fully grasp the concept of what happens in the CNC gantry, we need to understand the following;

Centre of gravity/mass
Forces
Moment

The Technical Explanation: CNC Router Forces

The design works by using a CNC drive system which is fixed at the bottom to either push or pull a gantry from left to right or vice versa. As this is happening, a router spindle is being moved downwards, and it begins the cutting action.

The movement of the gantry and that of the cutting action are in the opposite directions. This opposing motion between the two produces the cutting force in the design. The differences in the acceleration of the gantry, the chip load, and the revolutions per minute (RPM) of the spindle are the factors that determine the cutting force. The gantry material, the type of bit, and the RPM are the factors that determine the chip load.

As a reminder and for those of you that need to learn, force is equal to the mass of the body multiplied by the acceleration of the body. The unit of force is either in Newton in SI unit or lb-f (pounds of force) in the English system.

In the gantry, you will have a moment which is produced by the action of the cutting force. The moment is the product of the force and the perpendicular distance. Its SI unit is the N- while it is lbf-in in the English system.

To determine the position of the centre of gravity of the system, the weight of the gantry is needed. The centre of gravity is used as a term for the point at which your machine will be balanced.

To counterbalance the weight of the spindle hanging over the Y-axis linear bearings in a DIY CNC router, the upright side arms of the gantry are usually bent backwards.

In the design of a DIY CNC router, the centre of gravity of the gantry assembly should lie between the two linear bearings.

For a design with a moving bed and an immobile gantry, your CG should be located at the midpoint of sidearm bottoms of the gantry.

This is to give you the guarantee that the machine will not topple over and will remain in balance. It also equally distributes the loads on the bearings of the machine.

Summary

Below are some essential aspects you must always consider when you decide to carry out a DIY CNC router project;

When creating a distance from the linear bearings and lead screw of the X-axis to the bottom of the linear bearings of the Y-axis, the distance should be as small as you can obtain. You can also make the distance to be almost equal to the distance from either the top or the bottom of the Y-axis linear rods to the centre point between them.

The material you use in the fabrication of the spindle plunge arm should be strong and not easily bent. For the spindle plunge arm which is located on the Z-axis assembly, you must ensure that the length of the arm is the smallest length possible.

You should determine the centre of gravity of the gantry. This can either be by calculation or through a rough estimate, and the spindle should also be taken into consideration. To get the best out of your design, you should try as much as possible to have your centre of gravity between the linear bearings at the front and back of the X-axis of all the arms on the gantry. The arms are essential for balance. (CG should be located at ½ D4 and as close to X-axis lead screw as possible)

When considering the distance of separation between the upper and lower Y-axis linear bearing rods/rails, you should choose the maximum distance of separation. To allow the maximum distance of travel for Z, do not forget to account for the clearance below the bottom rod. (Maximize D3)

Other considerations

For the best DIY CNC router, you need an excellent gantry design. While this is the case, DIY projects are often limited by the budget and materials available. This means you have to make estimations and have mental pictures of how you can use the materials available to get a design that will work.

To analyze your design, you can contact us, and we can provide you with a free analysis. We perform an exhaustive analysis which includes;

Dynamic simulation of your machine
Specific CG location
Material selection

Material stress and strain analysis

 

Other aspects which are important in CNC router do it yourself projects include;

  • Motor placement
  • Lead screw placement
  • Linear bearing attachments

Links

Go back to step 1: HomeMade Hobby CNC Router Machine

Make My Ideas Home.


Linear Motion System, Step 5.

A linear drive system is just one part of a CNC router machine and is probably the most vital to get right the first time round if you dont that couples to your drive system will result in the CNC machine being pretty much useless so its imperative to get it right.

The linear motion setup has 3 major roles when it comes to your CNC machine.Linear motion

1) Support Other Machine elements
2) Guides the router cutter across the X, Y and Z with as little friction and resistance as possible
3) Supporting secondary loads like Torque, Forces, and linear friction etc.

A linear motion product consists of some kind of linear bearings and also the linear bearing carriers. With numerous different of sorts of bearings and guides, All with pros and cons. As a result of the incredible importance of this major component of any CNC router machine, it is absolutely vital for any buyer or builder to become familiar with the linear motion components.

There are too many areas to consider when looking at these components that that is wheather you are a buyer or a builder, both areas are similar but they do have slightly different consicences if the wrong decision is made.

Linear motion components come in many different varieties and they all will be covered in this article just read all the articles to get the decision right the first time round.

What a Buyer needs to consider

Poor linear motion components can be the downfall to any CNC router machine. For any individuals that are considering buying a brand new CNC router today, there ought to be some time spent looking into these elements of the machine as they shouldn’t be worn down or of poor quality. The performance and the build quality of linear components have massively gained better tolerances and improved in recent years, but on older second-hand machines they may not have been maintained or damaged which you will need to be able to pick up on. Pretty much all of the machines you will see at current date will be employing high-quality linear systems on their machines for purchase.

This is very true when it comes to mid-range and high-grade models. In case you are buying a low-end DIY CNC routers or cheap hobby CNC routers, its essential for one to have the ability to see quality linear motion components. Some manufacturers don’t specify what kinds of systems that are fitted and you need to realize how to identify faulty linear motion systems. For all those considering investing in a second-hand system you must be competent to know and understand linear motion components and be able to spot possible wear and tear already on the machine in question, you must know what sort of a linear components that can and are fitted and be able to recognise faults or at best be aware of right questions asked.
It may cost £8,000 or maybe more to change an entire set of linear bearings (this will be dependent on the system and manufacture). If the product is a few years old, the businesses may no longer stock and sell the various components. In the event, you must replace a component you could be left floating out at sea without a paddle. Therefore it is vital that you be able to find what components,and the possible issues to watch out for, and be able to find the replacements and see if they are still in manufacture by the said company.

There are many more areas that need to be considered when buying a CNC and they have many different components that you need to be familiar with and have a good understanding of so please follow through the guides I have written that will indefinitely help you with any purchase you decide to make.

What a builder needs to consider

The linear motion components will be the most costly and hard parts of any machine to get right on your CNC build. That is why it is vital to understand it properly and get it right the first time around so you don’t make many costly mistakes. If you’re here following the step 3 from the builder’s guide then I suggest you read all the sections that I have put together, rather than just the article your currently on how to build your own CNC this will help you avoid most mistakes you could come across.

This article will help and guide you through the numerous choices that you have that you can consider for linear systems components. It is going to discuss pros and cons of each as well as show you how to create your own in case you so choose. It will likewise include a lot of info on how you can mount the linear rails, linear shafts, plus a lot more, including worthwhile advice and design and purchase tips. For those who have any queries regarding linear motion systems, don’t hesitate to get in contact us with any questions you may have.

Like I have explained before there are many components that build up a successful CNC routing machine but mistakes made elsewhere are a little more forgiving, unlike the linear system which a mistake will mean a big overhaul on design and build and more money from your pocket.

Designing Linear Motion Systems

Designing linear motion systems are relatively easy and most people would be able to design them, The best program that you can use for them would be Solidworks there are plenty of detailed drawings that can be found on google, and if you don’t want to design them from scratch you can download them from here.

If you cannot find the linear system design files or have a design in mind but are unable to design it please feel free to contact us and we will work alongside you to complete your project.

Linear Motion Systems to Consider

These are some of the different types of Linear motion types that can but utilised by companies or for the DIY builder. They all vary in in price and some options are cheaper than other but cheaper isn’t always the best option all of this will be covered in the articles below.


 Overview of Linear Motion Components

In this section we will cover:

Types of Linear Motion Systems
Ratings and Terminology for Linear Systems
How Linear Motion systems work within a CNC
Plus More.


Guided Blocks and Rails.

In this section we will cover:

Rails and guided blocks how they work
The Terminology for Guided BLocks and Rails
Different Types and features
Manufacturers of Guided Blocks and Rails
Best place to buy and tips on purchases
Plus More.


Bushing and Rod Systems

In this section we will cover:

How rods and bushings are implemented CNC machine
Supported and Unsupported are the 2 different styles of linear rods
Different Shaft types plus features of them
Plain bearing and ball bearing bushings
Best Manufacturers to use
Best place to buy and tips on purchases
Plus More.


V-Groove Bearing and Track Wheels

In this section we will cover:

How you can use V-groove bearing and track wheels
Types that can be used and features of them
Best Manufacturers to use
Best place to buy and tips on purchases
Plus More.


DIY Linear Motion System

In this section we will cover:

Homemade Linear Motion systems overview
“Roller-Skate bearing” systems
Materials that can be used

Different Styles of DIY Linear Motion
And many other linear systems
Plus More.


Links

See previous articles for more information on your personal CNC router machine.

Step 1: Key design Choices, HomeMade Hobby CNC Router Machine

Step 2: The Base and X-axis frame Design Understanding

Step 3: The Y-axis Gantry Assembly and Design Understanding

Step 4: The Z-axis Assembly and Design Understanding

MakeMyIdeas Homepage

 


The Z-Axis Assembly, Step 4

So from the picture below, we can see two types of Z-axis assemblies and the Y-Axis CNC Machine Gantry behind the Z-Axis assembly.

Z-Axis

Just like the last discussions, when building or designing a CNC machine, it is imperative to understand the forces that are derived from its movement. By so doing, you can modify your design and also establish that it will meet the requirements of your design. In any case, for you to design and as well build your machine to meet your requirements, you need to acknowledge the forces that are involved.

 

 

Forces that are on the Z-Axis Assembly

Z-Axis

 

Let’s translate the above picture.

The dimensions are explained by the following:

D1 = the vertical distance between the upper as well as The lower area of Y-axis linear which bears rods and rails.

D2 = the distance between the upper and lower sets of Z-axis linear bearing which is vertical.

D3 = the spindle’s length attachment plunge arm.

D4 = the Z-axis assembly’s width

D5 = the horizontal distance between the Z-axis linear bearing rods and rails.

D6 = the plunge arm’s thickness

D7 = the gap between the cutting force (approx., a tip of the cutting tool) and 1/2 D2.

 

Now we have an understanding of what the labellings are, let’s have an analysis of the forces and moments.

 

Forces and Moments on the Z-Axis Assembly

Building a CNC router machine can be simple or complicated. Certain people over think and others just create it and check whether it works or fails. I think it’s best to mix the two concepts. So let’s understand what’s happening first.

The above image explains how the Z-axis assembly are assembled this is shown in a front and a side view. Take a look at the front view and observe that the Z-axis assembly is moving to the right while riding on the Y-axis linear that bears the rails and rods.

The plunge arm is at max Z travel and is as well cutting into a material as-as well as it goes from left to right. This action that is cutting creates a cutting force that connects the movement of the Z-axis assembly.

The cutting force is a variable of spindle RPMs, the number of flutes on the cutting instrument, the rate of feed, and the material that is being cut. You can know more on the most proficient method to calculate cutting force here. When setting up a CNC router, an essential choice to make is the sorts of material you might want to have the capacity to cut, which was talked about in stage 1.

For the primary time, just understand that there is a force in the other way than the Z-axis assembly is moving. Right now let’s see what happens due to this cutting force.

 

The cutting force makes a moment, which is explained in the image above as Moment A.

A moment is only force applied at a distance. We covered moments in more details in Stage 3.

 

Moment A = D6 x Cutting force.Z-Axis

Moment A torques the diving arm in the opposing direction of the cutting force, which torques the entire Z-axis assembly.

Br> This very moment results in resultant forces which are applied to the Z-axis linear bearing rails/rods and the Z-axis linear bearing themselves. (Yellow arrows)

As D5 and D2 increment length, the resulting forces reduce. You can see that when you are making a design or building a CNC router, it is vital to maximizing the horizontal distance between the Z-axis linear rails (D5), and the vertical distance between the Z-axis linear bearing block.

 

The Plunge Arm

D2 affects while cutting along the X-axis as well. See the image below.

The cutting force brings about another moment; Moment B.

B moment is the result of the cutting force being duplicated by the distance between the cutting strength and ½ D2.

Z-AxisThis moment will apply forces with a result on the Z-axis bearing. As the distance between these bearing (D2) increments, these effects will reduce. That is the reason it is best to maximize D2.

As a policy of thumb when setting up a CNC router, D2 ought to never be any less than half portion of the length of the plunger arm. Additionally, you want the thickness of the plunger arm (D6) to be sufficiently thick to not flex under your greatest cutting force.

The flex will rely upon the most extreme cutting force you are designing your machine around, the thickness of the material (d6), plunge arm length (D3), and the material it is made of.

If you require help calculating your cutting power you desire or the measure of deformation a particular material and size will have, you may get in touch with us. We offer free design consultation and other engineering services.

 

Conclusion

Remember the following when you design or set up a CNC router:

Maximize D1, diminishes the forces because of torque caused by the cutting force in the X-axis.

Maximize D2 diminishes the forces because of torque caused by the cutting force in the X-axis.

Maximize D3, yet still, permit your desired Z-axis travel.

Maximize D4, diminishes the forces because of torque caused by the cutting force in the Y-axis.

 

Different Contemplations

In later areas of the building, a CNC router guide, we will talk about other features such, for example, lead screws, motor placement, linear bearing and so on.

Do not forget that you may get in touch with us with any questions in regards to CNC machines in general or your design. We will help out any way imaginable.

The motor mount that is utilized in the above image might be purchased pre-fabricated from ebay or banggood for an assortment of router spindles.

 

Summary

So now we have taken a look at the initial four stages when setting up a CNC router machine,

Step 1: Key design Choices, HomeMade Hobby CNC Router Machine

Step 2: The Base and X-axis frame Design Understanding

Step 3: The Y-axis Gantry Assembly and Design Understanding

Step 4: The Z-axis Assembly and Design Understanding

MakeMyIdeas Homepage

Right now let’s keep on one of the most critical features when designing or setting up a CNC router machine system, the linear motion system.


X-Axis Frame Design, Step 2

If you are going to design and build your own CNC Router machine, the first thing you should consider designing is the Base Frame. Many people design their machines from the spindle down, but we are going to do it from the frame up.

Base Frame Oversight.

The base frame is and always will be the main structural element of your CNC machine. The base frame is what holds everything together and all your components will attach to.

The base frame design will depend on what materials and supplies you have got, the number of lead screws and motors your budget can cover. Firstly we need to cover the basics of the designs so we can buy parts to fit our design.

If for some reason you cant find a part for your design or your budget cannot cover your design you will need to go back to the drawing board and optimise your design and materials you have used. This is a common problem found by most when designing and building a project.

Firstly take a look at other CNC designs you can find anything that will benefit your own design.

Also, you must choose now whether you will be building a mobile gantry or mobile bed.

CNC Routers X Axis Frame Design

When you’re building your own CNC Router machine, the X-axis is the base frame axis, why because it supports the X-axis linear rails.

This part of the machine servers 3 main tasks:

1) It’s the main structural element, acting as the base.

2) Supports the X-axis linear rails.

3) Supports the cutting table.

The most used designs for the base are.

Fully Supported Base Frame

with a fully supported frame is one of the greatest designs it is also the main design used in industrial and professional router machines.

X Axis

The fully supported frame design means that both X-axis and Y-axis will rest on the floor or other structure. There is nothing across the Y-axis gantry (connecting). This results in a very sturdy CNC Base design that will not flex under the cutting table or its own or external weight.

For this frame design to be able to flex or deform the material would have to compress.

But keep in mind that the kind of flex we are talking about isn’t a massive amount, and if we revert back to the question in step one and that was how accurate do you want to build your machine and hold that accuracy. A deformation of 0.01 is acceptable if you only expect 0.1mm with your machine.

There are also drawbacks with this design they are, You will need to add an extra stepper, lead screw, ball screw and proximity sensor or limit switch, so this alone will bump up the cost of your design. You could employ a fully supported frame design and only use one motor (stepper) and use a pulley belt system, but for this system you would need to ensure your motor is up to the job as it will be under a lot of loads, this will be covered in the CNC drive system section where we will show you how to work that out. With the fully supported design, you can get away with lighter materials because it is supported by the floor and other structure.

Now on to the next design.

Full supporting frame vs full supporting linear rails.

This design is fully supported and does not have anything obstructing or sweeping across the axis while operating

later we will cover fully and end supported linear rails, but that is later, for now, we will just cover this heading, so focusing on this frame design it is possible to have fully supported linear rails and not have a fully supported frame like this.

X-Axis

partially supported X-axis fully supported Y-axis frame

The most common design found in the DIY hobby CNC router out there is this one.

X-Axis

This illustration shows Y-axis and ends support the X-axis frame.

In this design the gantry would be an undercarriage design that would link the Y-axis underneath utilising only one stepper motor lead screw and proximity sensor, this would allow for a fully supported linear rail setup, however, the supported rail will still flex but nowhere near the same extent of a non supported rail.#

a downside to this design is that you would need to add feet either end of the frame allowing the Y-axis undercarriage to pass back and forth without any obstruction, this would still be classed as an X-axis supported system since the frame would not interfere with the gantry.

This makes a very sturdy design because the Y-axis has no flex within it, it also makes for a very strong cutting bed that is also very rigid, only downside is where we have supported the x-axis up with legs this will allow for the X-axis to deform under the Y-axis weight or cutting force.

Building this frame out f solid aluminium measuring 38mm x 115mm with X-axis length of 1520mm your frame will sag 2.5mm in the centre. That is only under its own weight this does not include gantry weight or anything else like cutting force.

This would be a nightmare if (back to step one) you decided you wanted a machine with a tolerance of 0.01mm in the z-axis, this machine would definitely flex and you could probably compensate for it, but the machine could and probably would vibrate and bouncy even while trying to cut a straight line.

If you choose to use this design I would say to use a small x-axis length 600mm to 800mm max this would lower the amount of sag in your x-axis.

This frame design is the easiest design to set up and gets going but not without its known issues, there are other solutions out there for design.

Full Support on X-Axis Partly Supported Y-Axis

For this design lets say you only have one stepper motor and lead screw available for your X-axis but still wish to obtain a high tolerance machine. What we could do is move the Y-axis gantry inside the base frame, this would allow for a fully supported X-axis the machine would not be able to cut under the x-axis frame, however using this system the y-axis would not be a fully supported.

X-Axis

With this design you can see, the X-axis is fully supported (its grounded) however the gantry would be able to cut through any frame within the Y-axis so limiters would need to be in place to protect the frame.

With this setup no matter how much weight was placed on the gantry or cutting bed the X-axis frame would not deform rather the material would deform then cause an issue.

However, for this frame to work for the cutting bed would have to be separate from the overall machine, this means the machine table could deform if wasn’t built with adequate strength and support, there is also a pro to this design once the bed is set you could use your machine to plane it smooth and level.

This would mean the cutting bed is true to the machine.

When designing and building your own CNC Router Machine, you will have to decide what is more important to your design. Have a machine that remains constant or having a bed that will flex with your machine, this will be covered more when we cover the cutting bed.

Alternatives To The Above

there is always another alternative and depend on how creative you wish to get with your CNC router design.

We could create a design in which both X-axis and cutting bed are both very supported, if you look at my design below you will see the X-axis is raised this allows for a small gantry in height it is also fully supported x-axis frame it sits on the ground and carry all the weight, as for the cutting bed it could easily be integrated into the design either fixed to the machine so it can flex with the machine or a free-standing bed that will remain constant and milled to always sit true to the machine.

Mobile Bed Design

mobile bed

Personally not a fan, Why, well to make this machine the X-axis has to be twice the size of the cutting bed so if your bed is 500mm your X-axis would have to be 1m in length, large footprint small cutting bed.

But with the design, the cutting bed is fully supported and attached to the machine it also allows for the machine to plane the bed to sit true so it does have its advantages

your only need one stepper motor and lead screw to get it to work this is a great design if you wish for a small high precision machine that will not break the bank.

Mobile gantry machines are great for PCB and engraving machines.

Considerations to think about

So when it comes to designing and building your own CNC router machine, firstly you will need to consider what material you will cut the frame from as it will play a big part in your overall design.

Different materials will have different tolerances and all will deform differently, but the most common materials to choose from are:

1) MDF, easy to work with relatively strong but will flex and warp if in a humid environment.

Will degrade over time and will need to be remade.

2) Plywood, only use structural marine ply very strong easy to work with and can create a good machine but over time will become weaker and lose precision.

3) Aluminium Stock, flat plate, angle etc again this is a great material, but aluminium can deform very easily over a small distance so if your machine X-Axis is 1500mm it will need a lot of support to stop it flexing.

4) Aluminium Extrusion, this is probably your best option it is designed to have a very low deform over a long distance it strong and easy to work with but does come with a price tag. But your machine will last a long time and always remain strong and precise.

5) Steel. You’re not going to get anything stronger than steel to build your machine but you will need a welder and you will have to take into consideration the weight of the materials as they accumulate on your machine.

All 5 materials have pros and cons all can be used on your machine but consider aluminium and steel don’t mix this is a big NO NO as the aluminium on contact to steel will transfer all its ions to the steel causing galvanic corrosion and your aluminium will become worthless in months.

In future pages, we will be covering placement of components and these should all be considered into your design especially when it comes to maintenance of your machine components.

For now, just review your design you may consider different options for your design.

Do not rush your design it is important to find the issues within the design process before you start building as a minor error might mean a costly rebuild later on.

Next lets look at the Z and Y axis frame design.

Go back to step 1: HomeMade Hobby CNC Router Machine

Step 3: Designing and building the Y- Axis.

Make My Ideas Home.


Hobby CNC Router Machine, Step 1

As we described in the previous article, There are many pros to designing and building a custom hobby CNC machine.

When it comes to designing and building any machine you will come across many different problems so easy to fix others not so.

When designing a CNC machine you will realise how simple they are, the concept is pretty straight forward, but you can quickly run into issues in the process, but don’t let that deter you.

That’s is why I have created this Guide, to keep you away from the possible errors you will make along the way this will help buy keeping your costs and spent time.

This guide will mainly concentrate on the hobby CNC router machine, because these machines are relatively simple the guide could easily be adapted to most linear motion systems, for example you could remove the Z-axis and router and add just a laser to create a CNC laser cutter.

By reading this page you are probably considering building your own CNC router machine. You probably even have a design in mind, this is to be expected, at the end of the day its your machine build it as you wish.

This guide is not in place to change your design or tell you, you must build it this way for it to work, but rather supplement your design with useful and valuable information on your CNC router machine.

I have wrote this guide, in the belief that you have some general knowledge of how a CNC works, if not you may want to take a look at CNC Routers the Basics.

So Lets Get Started

1) Choosing the right designing

There are two main designs you can choose from for the hobby CNC, this may seem to contradict the fact that every machine build is different, but when you look deeper you realise there are only two you will ever encounter, they are.

1) Fixed Gantry, Moveable Cutting Bed.

2) Mobile Gantry, Fixed Cutting Bed.

You can see the difference in the two designs below.

Now will explain in more detail the difference in design.

The Mobile BedCNC Router design

You don’t see this all to often in the hobby CNC world, but there are still reasons for picking this type of CNC machine because they can be built strong and sturdy they are ideal for PCB or engraving machines, for these size machines they work well.

As mentioned above this type is very sturdy, because the gantry is fixed there is no flex In the gantry under load, this is because there are no components in place to allow flex ie linear rails and bearing sliders.

When using a mobile gantry you must take into consideration the mass of the gantry and use the approprate linear bearings on the X-axis. With a moble bed design the gantry its self does not move this mean you can build the ganrty as heavy as you need to reduce vibration to a minimum.

With ever pro there is a con and the con of this CNC design style. And one of the main ones is that when you increase the length of the X-axis the mobile bed becomes less efficient.

If your unfamiliar with the X,Y and Z Axis notation I have added a picture to reference better, as described in the basics of CNC router machines the X,Y and Z are always in this configuration.

On the mobile bed design when you increase the length of the x Axis you’re design will become less efficient this is due to the size of the bed, on average you will find the general size of these machines to be around 100 to 300 mm, I have seen larger but the design of them becomes more and more complicated.

With the Y and Z-axis you don’t really seen many changes in them.

In conclusion if you are after a small machine for engraving or for PCB work these are ideal, personally I have never built one a I don’t like the design.

The Mobile GantryCNC Router design

These probably make up around 95% of hobby CNC machine designs and this is the design style I would choose over the other. In this style the bed is fixed and has no moving parts the only thing that moves is the gantry is is beneficial because the whole cutting bed becomes useable unlike the mobile bed version.

The problem you will find is building a gantry that is light weight but sturdy, it will also need to be designed to fit some for of linear bearing assembly.

If you are not considering building a small machine then this would be the ideal design to go for. We will go into more detail about this later.

But for now you need to consider which size best to suit your needs.

2) The Cutting Area

The cutting area is the overall distance in which you can cut over, so if on your X-axis you have a 700mm linear bear you deduct the length of the two combine linear bearings so if X = 700mm – 200mm of the linear bearings you have a tool tip that can move 500mm on the X-axis.

So when it comes to your design you want to build it the right size these are things to consider which we will cover more on a later topic structural considerations.

But first off we will want to workout what we wish to cut its size maybe just A4 size or maybe a full sheet of plywood 2440mm x 1220mm we could build a machine this large but it will become expensive and your find many issues along the way so I suggest keeping your design small to start learn from your mistakes and then go from there.

Common issues with large machines can be that the mobile gantry that you would have to use could sag and have a lot of flex in it.

The cutting area is also known as the machines travel and this is the movement along the axis, this will be smaller than your overall machine size which will explain more in stage 3.

3) The Machine Size

Everyone one I know that has built a CNC machine has tried to build it as big as they can get even I did when I first started designing my first project, but there’s a few issues to cover.

Do you have the space for such a large machine whether you built a shed solely for it or its going in to your garage.

Allow room so you can easily move around your machine when it come to repairs or modds do you want to have an easy job doing them.

Money, the root of all evil and the same with you massive design, problem is ACME lead screws and linear rails don’t come cheap and more weight bigger steppers.

So with my current machine I have a space 700mm x 700mm so my machine would be this size to fit its also an easy size to manage and repair.

My Footprint is 700mm x 700mm so how big is my cutting area I cover this in more detail here, but briefly if your gantry is 400mm you would want your bearings to be around half that distance so 200mm this is taken away from the overall linear rail size. 700-200=500mm cutting travel.

Aim your design at having as much travel distance as you can possible achieve.

4) The Machine Tolerance

The ideal of having a CNC router machine is to complete your jobs accurately more accurately than if you was doing it by hand.

When designing your machine you must consider accuracy and precision and these 2 things should not be confused as the same thing.

The image below shows.

Homemade CNC Router Machine

Accuracy is the machines ability to machine with tight tolerances.

Precision is the machines ability to perform the above repeatable.

Your machine should be both accurate and precise and hold and maintain this. For example you maybe able to cut a piece is within 0.01mm but repeatability might be 0.10mm.

Most people design there machines and live with how they perform overs try bettering the accuracy and precision.

There are ways to build your machine so that it is both accurate and precise if you are happy with a 0.10 mm machine then and that’s all your ever need so be it.

But if you want a machine that is 0.01mm repeatable then there are some design requirements you must include into your design in order for it to perform so well.

Typical hobby CNC routers can hold tolerances of between 0.01mm to 0.10mm however, this is your decision on how tight you want your tolerances, but make note the larger the machine becomes the more costly it becomes to reduce them tolerances.

5) Materials and Tools

Materials first so what are you going to use for your design Aluminium, MDF, Plywood Plastics Steel.

The material of which you choose should fit your budget building a machine fully of aluminium can become very expensive quickly.

Does it matter is MDF worse than aluminium “no I have seen MDF machines hold tighter tolerances than one of aluminium.

It is crucial to pick your materials before designing your machine reason being is the right material for a wood machine is not always the right material for an aluminium machine.

Tools steel is not to hard to work with but you will need a steel cutter and posible a welder.

Aluminium can be tricky requiring a special cutting disk and drill bits and router bits can become clog to.

Plywood MDF and Plastics are the easiest to work with easy to cut and drill common toolling can be used.

Most people build a UGLY machine first normally made of wood they then use the UGLY machine to build a nice fancy aluminium machine.

If you do not have the right tools to build your CNC this will show in your machines tolerances.

We will look at the properties of materials later, this will allow us to calculate deflection within SolidWorks find weak spots and amend them before we start are build.

It will also help you in designing your machine to the load ratings you specify.

6) Budget

Last one on the list, for most of us me included this is the biggest restriction in your build for instance I would love a machine that had a ATC spindle but my budget suggested otherwise.

You can easily make an expense list in spreadsheet covering all costs.

After all what’s the point in spending loads on a hobby machine when it might all accumulate to a cost you could of got a low range machine prebuilt.

Example of a Budget Spread Sheet.

Summary of what we covered in part 1

1) Choosing the right designed

2) The Cutting Area

3) Machine Size

4) Tolerences

5) Material and Tools

6) Budget


CNC Machine, Machines cost.

The prices of CNC router largely depends on the CNC’s Specifications and the extra components that you have added on. There are an extensive variety of CNC router to choose from. Most machines are intended for a particular scope of abilities. General cost ranges for the CNC routers are as follows.

Hobby CNC routers Price Range: £500-£3000

Hobby CNC routers normally come in packs. The size varies from 300mm by 300mm to a 3m by 6m. These machines are typically made for specialist or domestic businesses. The handcrafted CNC router is generally made of plywood plastic or aluminum with extremely fundamental features.it has Stepper engines and ACME screws that steer the 3 axes framework. The controller system might possibly be incorporated. There are no additional features attached. The resistances might be somewhere in the range of .01 to.001 repeatable.

Low-End CNC Routers Price Range: £3000-£20,000

This value of this range will fetch you a router up to 4 by 8 feet. These routers are a stage over the Hobbyist machine routers. They are intended for light work. They work on 3 axes with the Z axis or the vertical axis being restricted to around 6 inches of range. These routers may likewise be received in a kit, and you may need to assemble some of it. The CNC machine Prices will differ significantly this all boils down to the choice of spindle motor fitted. The spindle is normally a regular router or a mechanical router spindle with 3 to 6 HP for the highest limits of the price range.

The CNC router systems of the low end might possess a dust collection framework although a vacuum system and some other feature will incur an additional price. The composition is normally good quality aluminum or a steel system for construction. These routers normally have a complete set of supported linaer rails and bearing blocks. What drives the low end router is normally a ball screw assembly fueled by stepper motors or a fundamental servo system. The resilience might be somewhere in the range of .01 to.001 consistant with right mantinace.

Middle-Range, Price Range: £20,000-£50,000

These kinds of models are like the lower end router models. Be that as it may, the composition is normally considerably heavier. The casing is basically steel plus it is strengthened. The 3 axes framework is controlled by a servo closed loop system with rack and pinion, mainly on the heavier axes X and Y and a ball screw on the Z axis . The CNC machines controller ought to be incorporated. There ought to be a dust collection system and a mechanical style router shaft. addtional features like a ATC  automatic tool change spindle will mean you will pay alot more for it.

This kind of router is generally found in companies that are into sign production or other flat board cutting applications. The prices of CNC router will largely depend on the seller in this range. Now you may discover many machines with comparative specifications yet you will have to pay more for some specific brands. The resistance may differ from .001 to .0005.

Top of the line Routers, Price Range: £50,000-£80,000

This price of this CNC machine range is meant for high demand industrial name brand models. These engines might be close to 2.5m by 10m possible even more. These routers size is up to many tons and is completely steel constructed. These CNC machines possess the best segments affixed and will come as a fully finished system. They may likewise incorporate components like ATC shafts and an independent vacuum system. The computer and controller must come as a module. The company you decide to buy from, should provide training courses and compilation for an additional charge. The router accuracy must be the best in their group running from .0001 to .0005. Be that as it may, these machines are generally still only 3 axes frameworks.

Price Range of the Highest End Models: £80,000 and up

These CNC Routers are the greatest and best accessible. CNC machine in this category may possess 4 or 5 axes. Substantial plants and companies may possess a few machines for the essential part of their production. Within this price range, accessories and features should be made available.

Some other Considerations

Whenever you are contemplating on the price of a CNC router, bear in mind to incorporate extra costs that you can incur, for example, shipment, fixing, tutorials, guarantees, and the software could rapidly amount to many thousand pounds.

Delivery and fixing

The size of CNC machines can vary from a couple of hundred kilos to a few tons. This can cause an extra fee with transportation expenses. A few organizations have a selective service that is incorporated into the cost. Be that as it may, in the event that you are getting one, make sure to make plans with the seller before resolving to purchase.

For the bigger machines, be ready to make plans for the machine in time. The floors may require reinforcement, entryways extended, and so on. Additionally, don’t ignore the power and electrical prerequisites. A lot of these machines need 220/3 stage or another top of the line power necessities. It ensures your wiring is adequate.

These routers will in all likelihood come in a few pieced and should be assembled and fixed. It is beneficial to have an expert with enough experience to fix these machines. A lot of the producers or sellers give their services yet be ready to pay something from the range of £150 to £800 daily for fixing. You might need few days to install these CNC Router machines.

For low-end models, it is adequately reliable to contract a mechanic or carry out the assembly yourself. Be that as it may, for bigger CNC, it isnt worth the danger of annulling guarantees or destroying the machine by getting it installed yourself.

Training and Warranties

These routers have a specific amount of information to absorb to be able to saftly operate them. This depends on the person operating it, it might take a couple of days or a couple of months to gain the fundamental skills to work these machines. The machine might be as effective as the individual operating it. Many organizations provide training for these machines, the price may be up to $1000 a day for a coach to visit the worksite. Be that as it may, a few organizations give instructional classes at their site.

Bear in mind to keep an eye on warranties and the coverage. Try not to place yourself in a circumstance where you would void the warranty.

 

 

CNC Machine Software

As a company or as a hobbist you are going to need some kind of design software bundle, for example, CAD software and CAM software to program the device path. There is an extended range of packages available that should be compatible with almost any machine. These bundles will normally need a yearly license charge. Be ready to pay any amount from £1500 to £12,000 for a total bundle.

For the low-end machines, there are free projects available yet they more often than not have restrictions.

Conclusion

The CNC machines prices are largely dependent on the abilities of the machine. Often time individuals overestimate their necessities. Acquire the machine that is ideal for your job. Be that as it may, in the event that you feel that what you need will change sooner than later, it might be less expensive to put resources into a higher end router first. The CNC router costs might possibly be advantageous for your business. Record the costs and think about them against the savings and potential change that a CNC switch could give.

These CNC router costs are general and are in no way, shape or form all indisputable. As the business advances, so do the costs. Costs may reduce or increase.

On the off chance that you are keen on purchasing a used CNC machine, I propose you look at the postings at Ebay.

They provide an awesome service connecting purchasers with sellers. Look at and contrast the used CNC router Prices and the new ones, there is also price quotes through their website which is very swift. Take time out to check it, you may save some cash. Simply carry out your research on the item before purchasing.

On the off chance that you want the New CNC routers, at that point, an awesome approach to get a few price quotes instantly at Buyerszone.com

Buyerzone is a free webtool great for finding products to benefit your company needs.

You will be linked to a section of their site that deals in CNC routers via this link. You can rapidly check various prices of the CNC routers that suit what you need most. Basically, fill the form and submit.


CNC Routers, Types and Features.

So you have ready through the How CNC drive systems how it all comes together. And now have a basic understanding of how they work.

Large Scale Industrial CNC Routers

CNC ROUTERIndustrial CNC Routers is a rather general term, they make up around 80% of the CNC’s known. Where I work on my day job Prater Ltd they use Elumatec CNC’s even previous companies I work for use a variety of CNC’s we used to machine Windows Doors and curtain wall systems.

Being that they are used in the industrial market they are generally large in size and a lot more expensive.

This is due to the fact that they are built to operate for long hours and harsher conditions. This makes them the ideal assistant for any company that wants to make a profit.

Industrial CNC comes with a lot of key features these are.

Faster Cutting Speeds

ATC Automatic tool changers

Vacuum beds or pneumatic clamps

Extractors or Oil Coolers

High Torque and Speed Spindles

And More

one of the best companies supplying machines are Matsuura CNC’s they have no limitations they have from 3 to 6 axis if you are interested in buying a CNC check out the buyer’s guide.

Mid-Range CNC Routers

Below the industrial grade CNC machines we have the mid-range CNC machines, they are precise and accurate.

In Most ways these machines are very similar to the industrial only difference is they are generally a little bit smaller.

They run from desktop size to full size around 1.5m to 2.5m these machine sizes are more sort after by the hobbyist and smaller businesses.

These are the types of machine you would find in sign makers workshop. Price range is also around the small as most hobbyist CNC machines. They don’t generally come with vacuum tables or extraction system installed but you can normally source these as add-ons.

These machines are a lot harder to find probably due to the fact that there isn’t a large enough market for them.

Hobby CNC Routers

These normally are associated with the DIY Homebuilt CNC’s they are normally designed and built by the owner. If you search google for CNC Plans plenty will come up.CNC Routers

I feel that designing and building one or buy a kit is the best option as you get a better understanding of how the machine works.

When you see these machines on the internet they are normally designed around budget and what they can find the make them from.

If you know what you are doing you can easily build one that would take on a mid-range CNC maybe even an industrial one.

If you are interested in building one of these we have a few plans available here.

In the above 3 headers you will find the common CNC Routers but theirs more available.

Multi Axis CNC Routers

6 Axis CNC RoutersAll of the above have 3 axis if the only have to they are just drawing machines, however, we can go in the opposite direction like 4, 5, 6 axis machines these are a lot less common but still available.

4 axis CNC this normally means that the spindle can rotate 180 degrees.7

5 axis CNC these the spindle head can rotate in 2 different directions

6 axis these are the rare ones they normally come in the for of a robotic arm with a rotating bed.

4 and 5 axis CNC machines are able to create true 3d parts, where 3 axis are limited.

6 axis is the only true 3d model cutter as they can come from every angle.

We now have linuxCNC covering 4th and 5th axis work you can now convert a 3 axis to 4 and 5 axis using an adapter.

Speciality CNC Routers

These are normally mistaken by new buyers that see these machines on eBay cheap so get one, they are good machines but they won’t cut wood they are more engravers.PCB CNC Router

So what is an engraver they do things like PCB boards, 3d engraving and so on?

CNC engraving is very popular this is probably due to the cheap entry costs the world of CNC’s

people do everything from trophies, tags, plaques, they have a working area of around 12 x 12 inches.

CNC PCB machines are also small normally smaller than engravers. And are great if you’re in to electronics you can design and machine your own circuit boards, no more etching.

Summary

As you can see there is a great variety out there and it all depends on what you are out to achieve.

Most machines are not limited to just wood but check with the Manuel otherwise you could burn a component out which will cost.

But remember you still have the option to design and build you’re own as you already got this far why not go further plus save some dollar doing so.

Now we can move on to the next area that is router prices and information.

Links

CNC Routers the basic guide.

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