CNC Drive Systems How It All Comes Together

How it works

A CNC or Computer Numerical Controlled Router these work pretty similar to a hand router where the operative would move the router to create what they wish to achieve.

All CNC machines work in a similar way, they use a computer programme that communicates with the breakout board which breaks down the signal to the Stepper drivers and then they turn the steppers to the right position of rotation.

A standard CNC router machine moves in three directions these are you axis, they are referred to as X, Y, Z directions. X and Y are normally the longest as they run front to back and left to right. Z is the height up and down and is normally the shortest this is to do with the torsion stress they will be explained in a different article.

See below the for a visual.

CNC

CNC Machines work very cost-effective they work all three axis simultaneously which reduces the amount of time the machine is running. This means you can create a high definition model accurately.cnc

The Parts

Ok so now we will go over the parts on a CNC machine, and how they all tie together the make your machine work.

T the right you will see an image showing the Parts.

There are many more parts to a CNC but you don’t need to know them just yet.

Now we can look at these parts in more detail.

The CNC Controller and Computer System

These two parts work directly together as the brain of the whole system. Telling the steppers and stepper controllers which direction to move and how much. You have to put your design into the computer software for it to do so.

Most of my designs start in SolidWorks and then get put in a cam program that formats it into a 2d digital image (dxf) they then allocate a tool path code such as g code.

The computer software then converts these g-codes into signals to the breakout board then on to the stepper drivers.

This is all done by varying the current and voltages.

Most CNC programmes like LinuxCNC and Mach3 are plug and play and only need a few things setup to get your system running. All will be explained in future articles.

The Spindle

cncThe Spindle is the part that holds the collet which holds the milling tool that does all the cutting.

Think of the spindle as a standard wood router you would find in any tool shop.

They are rated in horsepower in English units and watts in SI units.

The spindle rotates at high speed 4000 to 30000 rpm (Revolution per minute) these motors are great for cutting through material like wood and plastic.

For cutting metals you would need a spindle that cuts between 2000 and 10000 RPM.

Most CNC machines that are purchased are capable of cutting through both metals and woods, this is limited thou to softer metals like aluminium.

When cutting materials like aluminium you will need a means of cooling this, this is normally done by using an oil mist system.

This cools the router bit and material being cut and enables the machine to make a smooth cut.

Some CNC spindles are controlled by a VFD or variable-frequency drive these can control the Spindle torque and speed this very useful when you use a variety of materials.

There are also other options to that could be installed on your spindle these are ATC this is an automatic tool changer.

You will even use a touch probe at some point for calibrating your z axis check that out here.

The Cutting Floor

The Cutting floor is where you will place your workpiece, so this is where the magic happens. The cutting bed comes in many different types but they are all essentially the same.

They are designed to support and secure your work pieces to the machine.

Two of the main cutting beds you will find are t slot and vacuum tables, t slots work very well but you have to be aware of the clamps on your workpiece, with a vacuum table you don’t need to the clamps the air vacuum holds the workpiece in place which is great.

Vacuum tables have some downfall’s thou these are, you can only really use flat workpieces with them due to the way they work.

T-slots are a lot better if your workpiece isn’t flat with the clamps you can virtually able to clamp anything it’s a little more time consuming but at the end, you will have a finished product.

There is even a hybrid table which combines both vacuum and t slot together this brings on the best of both worlds but comes at a cost.

The Linear System

Each axis has a linear system in place to move your machine to its desired location, these include stepper motors or servo, a linear bearing or rack and pinion, these make up the linear system.

The stepper is where the electrical pulses from the stepper driver are converted into rotations this, in turn, rotates the linear bearing, this is the same if you used a servo or rack and pinion system.

So we have two different types of motor these are steppers and servos, stepper motors are defiantly the cheaper of the two they offer great performance and are very accurate and reliable, but they can generate a lot of heat, and they are not usually closed loop.

Servos, on the other hand, are closed loop and this means after they have moved to their desired location they send a signal back confirming they have completed the task.

You only normally find closed loops on high-end CNC as they are reactively expensive to buy.

Controlling servos is still the same you will need a servo controller in place but they are not the same as a stepper controller.cnc

The stepper or servo offers the power in the for of rotation motion which then needs to get converted to linear drive. This is where the lead screw comes into play, this is essentially like a threaded rod and a nut, the nut is held fixed to the gantry as the tread rotates the nut either moves up or down the thread creating linear motion.

With a rack and pinion the stepper motor or servo is attached to the pinion and the rack to the frame as the motor rotates it creates linear motion up and down.

Both systems have their benefits and drawbacks it’s just a matter of what’s better for your system.

There is more information on this here.

Features

Pretty much all CNC machines you see today are gantry style CNC’s this is where the whole of the y-axis is suspended across the cutting bed. It’s suspended via two arms allocated either side of the cutting bed on the X axis linear rails.

Summary

By now you should have a good understanding of how a CNC system works. The Computer runs a program which sends signals to the breakout board where they are broken down to the drivers and the drivers send electrical pulses to stepper motors and the turned into rotational motion and the lead screw then converts this to linear motion.

This moves the spindle in 3 directions that can accurately cut your model.

So this has only covered the basics of how a CNC drive system works. If you’re like to find out more in-depth about parts and other related parts to a CNC, Please check out my other pages.

If you are now comfortable with how the CNC drive system works we can move on to the next section which will take a look at the different types and features that are available.


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Comprehensive CNC Build Guide

Your DIY CNC Build starts here

Introduction CNC Build Guide

So if you have made your way to this page you must have decided or considering building your personal CNC router.

So where are we going to start?

There are hundreds of reasons for owning your very own CNC router.

DIY CNC routers can pretty much cut and shape any material as long as they are built to do so.

For the general hobbyist or weekend DIY Guru, This can open literally tonnes doors, and open up your product capabilities.

Building your own CNC is great news for your wallet as the build cost is far less than that if you brought one.

And the truth is you can build one as good or if not better than anyone you could find pre-done. Building one is not difficult either and with this guide, it will be even easier to complete an awesome end product.CNC

You also get a great deal more freedom in designing your own, you can design a CNC machine that fits perfectly to your own personal needs.

Many people choose to design and build their own CNC machine, one main reason is buying a machine ready to go is extremely expensive and may not fully fit your requirements.

Or you may just like getting to know the “inns and out’s” of how they work how they go together.

There is such a large learning curve to it and it makes you feel humble knowing you know every aspect of your machine because you designed it built it and run it.

Make My Ideas Experience

When we first set out the challenge of designing and building our first CNC machine, we thought we had it all worked out but issues and questions soon arose.

Simple questions and issues like:

What is the difference between supported and unsupported rain which do I need.

What to build my machine with will it be sturdy enough

do I need servos or steppers

And a lot more…

Due to working in the CNC industry and having a good general interest in engineering I could eliminate a few of these issues.

Luckily an engineer of one of the machines I use had been tinkering around for years building his own personal CNC router.

I gain a lot of wisdom from him and learn a lot from the mistakes he had made along the way.

I also read through hundreds of threads relating to my issues, on many different forums like CNCzone.com, Which is a great resource of information.

The only Problem with the forum is that most of the answers I got to my question kinda contradicted so I still didn’t have closure on my questions.

In the end, I was just buying what I thought was right and trying it out sometimes this worked fine other times I’d end up with a lot of stuff that wasn’t any good for anything, thankfully eBay became handy sell unwanted parts and also finding a few components second hand to test.

This was a very good learning curve as I got to see how a lot of parts worked why they didn’t work and how I could possibly implement them into possible future projects.

CNC Machine Kits and Designs

You can find many kits online at the various website but I am yet to find one that would cover all my needs they seem very limited in design features and you could have a lot of issues in add additional parts onto them.cnc

Another problem with a kit is you are not going to fully understand how they work and how key components work.

But if you want to be fully aware of how a CNC machine works then following through all the information on this site and designing and build your own fantastic machine is the best option you have.

If you still not wanting to design one but build it we will be putting together a few plans that will be fully documented with Videos going over the design procedure, a base more with room to add on key essentials to meet your needs.

And if none of the plans meets what you have in mind you can contact us and we can put your idea into a design for you.

In The Guide

What will you find in this guide, hopefully, everything you need to know and more that is our aim?

After years in the industry I have been able to pick up a vast understanding of these machines and their capabilities and their failings, Plus I have been fully trained in the use of SolidWorks and all of its functions so designing and spotting their flaws before it makes it to the build phase and wasting money in the long run.cnc

So with all of the above, the guide is aimed at saving you the unwanted waste of time and money from possible design, material and components decisions.

So what’s to be covered literally everything will be covered, why because I even made mistakes when I come down to bolt selection on one of my builds.

We will cover the Pros and Cons to every component you will be considering.

At the start, you think of these machines as 3, 4, or 5 axis machines but at the end, you will realise that there’s more there’s the mechanics the physics the software plus the rest.

Even if you have already started a design I will say you must read through the guide as you might pick up on some issues or even a little idea that will drastically improve your design.

By the end, you will have so much information to make the perfect machine that will be able to cover everything you original design it to do.

 

Time to Get Started with the CNC Build


Step 1, Basic Design Discisions

CNC Router DesignIn this section we will cover.

Identifying the right design for you
Required cutting area
Space availability
Materials
Tolerances
Constructing Methods
Available tools
Budget


Go to Homepage from the DIY CNC Machine


How to get a GeForce graffics card to work in SolidWorks (realview)

SolidWorks GeForce RealviewOne of the most annoying things about SolidWorks is the none existent support for Geforce cards,

But there is a workaround for this and this video details how to get around the issue and get realview working.

How To

1.) Open up the registry editor (Start Button - Run... - "Regedit")

2.) Navigate to "HKEY_CURRENT_USER\Software\SolidWorks\SOLIDWORKS 2015\Performance\Graphics\Hardware\Current"

3.) On the right side double click on "Renderer"

4.) copy (ctrl+C) the Value

Since I have a GeForce Card mine is "GeForce GTX 960M/PCIe/SSE2".

5.) Navigate to "HKEY_CURRENT_USER\Software\SolidWorks\SOLIDWORKS 2015\Performance\Graphics\Hardware\Gl2Shaders\nv40"

6.) On the left side (the tree view) right click on "R420" and choose "New / Key"

7.) Rename the new key with the copied value (ctrl+V)

8.) Click another Key and back to your newly created to make sure you are editing the right values. The right side should be empty but an entry (Default) whose data is "value not set"

9.) right click on the right side and create "New / DWORD (32-bit) Value"

10.) Rename the DWORD to "Workarounds" and, after that, double click it

11.) Leave the "Base" to "Hexadecimal" and enter 30008 into the field "Value data"

12.) Leave the Registry Editor open and start Solidworks. Create a new part / open an old one and try to enable RealView.

If RealView is still greyed out:
13.) Close Solidworks and go back to the registry editor. Doubleclick the DWORD "Workarounds" and change the "Value data" to 30408 or 40408
14.) Fire up Solidworks and try again to activate Realview (Part or Assembly open)

If RealView is STILL greyed out:
15.) Freakout - I can't help you mate.


SolidWorks How To Add Weldments Profiles

SolidWorks How To Add Weldments Profiles

SolidWorks, Adding weldments profiles is extremely easy once you know how theirs a few must follow steps in getting it right,

That is why I have created this video so that you can gain the knowledge that I have and use SolidWorks to its full potential.

solidworks