1

Hi,
On my CTC (black plywood version), I’m having problems with ABS parts lifting… I’ve tried blue tape / glue / hairspray etc… however I believe that my bed temperature may be low…
Measuring on a Fluke 187 it reads only around 70 degrees at the highest setting (120 degrees) That’s measuring the aluminium at several points… from the top.
When in simplify3d… I can set 140 degrees and switch the bed on, and I can then read around the 90 degree mark…
Testing this theory I printed something while at the same time blowing a hot air gun on to the bed… and it was the only print that actually stuck and came out well…

I’ve also covered the sides/front and a little of the top with foil and ambient temperature is around 40/50

Has anyone else had an issue like this?

2

I have problems with parts lifting in ABS too and I have a fully enclosed printer (Makerbot 2X 4th gen), I’ve never measured my actual bed temperature though but it’s set to 110. I assume you’ve tried ABS slurry on your print bed? That did work for me but it was hard to get the prints off. Same with BuildTak which I recently tested for the first time, it is amazing to get parts to stick and not warp but then it is difficult to remove prints (but easier than ABS slurry).

Can you measure the actual heating element? That would give you a gauge if that is not heating up to the correct temperature then you have a problem there otherwise if it is heating up to 120 then you may need to make an enclosure for your whole printer/bed.

Hope this helps

Andrew

3

Thanks for the help. On the actual thermocouple in the centre of the PCB(body & solder joint) it peaks up at around 89.6 degrees… This is when I set it to 120 degrees and the front LCD says it’s at 120 degrees…

Is there a software tweak to correct this or a resistor / calibration tweak somewhere perhaps?

(PS… I’ve not tried buildtak yet as I’ve read some mixed things about it on ABS… Willing to try it out though and it’s on my list…! But I’d like to get the temperature thing sorted first as I’m starting at only 90 on the thermocouple… And 70 degrees on the actual aluminium. I measure only around 50 degrees on the top of the 3mm glass I’m using… If I can get everything up by the 30 degrees that would bring it in to calibration, I think I’d have a much better chance with 70-80 degrees on the top glass…

4

Sorry I don’t know much about thermocouple calibration, I suppose you could install a new one and recheck and if it shows approx 90 degrees (when the LCD says 120) then it is a software problem somewhere and the thermocouples are probably ok. Then you know it’s a software problem. The 40 degree difference between the thermocouple and top of the glass is quite a lot so perhaps also work on trying to seal the enclosure a bit more thoroughly? What ambient temps are you printing in? I found that this made quite a difference to my prints.

Cheers

Andrew

5

I’ve closed off all sides & top now… (not airtight… but most large gaps filled) & generally during a build the ambient inside the printer is at around 30 to 35 degrees…

Then with leveling the bed a little closer so the first layer is over-squashed… and upping the amount of hairspray used, I’ve gotten a couple more successful prints… This is with 120 degrees set on the machine… When cooled down, the print isn’t stuck to the bed at all… although no warping or lifting during the build… however I’m probably right on the edge between successful and lifting.

Apparently Sailfish allows a 130 degree temperature to be set… so that could help too to give me a little more adhesion…

Then yes, changing the thermocouple is possible… Although I’m not sure what particular part I need or if there’s a circuit problem…
Or I’m thinking upgrade the bed altogether at some point so perhaps just doing the Sailfish upgrade and setting 130 degrees would be ok for now… Is a silicon heater on the underside of an aluminium plate the best solution for a heated bed? Rather than PCB?