One of the biggest issues with the CTC 3D Printer is that the Thermistor is cheap and of the wrong spec for the application.
As the CTC is made in china it is built up of the most cost effective (normally the cheapest possible components.)
But we all knew this from the start as the price tag is very low.
Why is the Thermistor Wrong?
So why is it wrong, after printing on my CTC printer many times I found I have a lot of ABS prints warping and lifting off the heat-bed and wasting a lot of filament on bad prints.
So ideally the optimum heat bed temperature is 110°C to print ABS and PLA is 70 to 80°C and is the heat bed doesn’t reach this optimum temperature the print will cool and shrink and this is what causes the print to warp.
The original thermistor fitted to the heat bed is 50 ohms at 20 ° C and should actually be 100k.
As described in a number of forums, the CTC also showed me a much too high Heat-bed temprature. To compensate for this you had to heat the bed to 100 ° C, to get to actual 50 ° C.
Considering the heat-bed has a max setting of 130°C which only donates around 65°C high enough for PLA but to low for ABS.
The best and only possible solution is to remove the old thermistor and reinstall a new better one. The one i choose to use was the,
THERMISTOR, 100K, 5%, SMD, NTC
- Thermistor Type: NTC
- Resistance: 100kohm
- Thermistor Tolerance:-5% to +5%
- Beta Value (K):4100K
- Thermistor Case Style:0603
- No. of Pins:2
- Running Temperature Min:-40_C
- Operating Temperature Max:150_C
- Temperature Range:-40_C to +150_C
To install the NTC to expand the print bed temperature range. You need to remove all wing on the underside the ones used to adjust the bed height, press the tab and remove the rear connector from the heater bed.
Unsolder With the soldering iron the old and new NTC SMD solder version on the smaller SMD pads.
Original built and new NTC SMD variant below
The original still solder on and the new SMD in bottom left.
NTC unsoldered and pads cleaned the larger pads are for the original NTC and the to smaller and closer tabs are for the new SMD NTC.
New NTC as SMD component, these can be tricky to solder on as they are extremely small 1mm x 2mm in my case.
After installation of 100K NTC printer bed will now display the correct values.