Actually I checked today and this bed as somewhat more thermal inertia that the glass, Thus, preheating is a good idea
Might order one of these. How are you guys finding it with Edge and ABS ? Are you needing any additional bed stickies to get good adhesion?
I ordered and paid in old GBP's before the turmoil but have yet to receive it. Boris might slap extra duty on it to top up the treasury coffers to pay to the NHS or was that to Rupert Murdoch! That's my politics for today!
A bit. Plate at 60 and 210 is ok but then overhangs suck. I printed two benchys. The second one with 55/190 which was very good in the overhangs but the edges of the first layer warped a bit...
60 is not enough. I will need to play with settings a bit and use brim. BT in the worst case I go back using additives to the pei, but it would mean pei is no good for the price.
I tried 65 and 70 too but then there is the issue with the overhangs even worse you mentioned... The problem is the hot air from the hot plate keeping then PLA soft... I wouldn't say it is not worth it. It has just its special use cases. With the PET based material I have very good results. Just the PLA shows issues so far...
I will play with it and see, worst case I have resort to Carbon fiber or add some hair spray to the pei Also I think you need to keep it very clean or rather dirty, like for kapton
Hi Guys, I finally got around to do some testing of the bed surface temperature lag. And here it is: As you can see it takes the heater about a minute to reach 60C, but the surface only just reach 60C after about 6minutes. This is especially important with PEI surfaces since they only work when heated appropriately. This means that if you start a PLA print (60C) the print starts when the surface is under 30C and thats bad! @Alex9779 this might be why you have ben struggling with PLA on PEI?
I did some tests myself and I found that my print temps are fine when I start a print. The temperature distribution is very constant also on the edges. I change my heating procedure for the PEI sheet and then I thought it is good for the glass too so this new sequence is included in my latest script and profiles, I first heat the bed to 50°, then I home the head and start heating the bed and hotends to the desired printing temperature. This worked well for me. My lasted struggles printing PLA have been problems with a too hight plate temp so the heat sink overheated and the filament got soft in the heat sink and not really clogged the nozzle but the extruder could not extrude any more. It seems the Dual Titan design has some temperature jam if the bed temp is set too high. I dialled it in for PLA now at 62° for the bed and 200° for the first two layers for Colorfabb PLA/PHA and have good results with these settings... The Heat sink still get to about 50-55° but that I ok so that material does not get soft in it...
That lag improves substantially if you use the heated bed supports here to gently push the heater up to the aluminium. I think @Alex9779 uses small springs to achieve that effect.
That was my concern Alex and I have been looking at how to improve the airflow around the heatsinks. It appears that the fans are working against each other. I am about to print the X assembly and mounts but want to be sure on the temperature performance before making that final commitment.
Not really, I have a base plate where I mounted M8 screw upside down with lock nut and washers where table like parts sit on. I have 7 of them in the middle under the bed... Yeah well the problem popped up when I just increased the bed temp to 70° to get a good adhesion and realised that at various points on layer one and two the extrusion stopped. I debugged about a week and found yesterday when I pulled the filament out that it was thickened in the area where is has been in the heat sink. So I measured the temp the heat sink reaches if the nozzle is at 200-210° and the bed at 70° and found the heat sink gets over 70° which make the filament soft in there. not enough to clog in the heat sink but to get a little thicker by the pressure from above from one point the extruder is not able to push it any more. So I played with the temps and found that the adhesion is ok at 60°, but better for smaller details on the first layer at 62-63° and did the test with those temps again and then the heat sink temp does not get over 55° so this is ok for the filament to stay solid in the heat sink... The problem popped up when I switched to PLA/PHA, no problems with Edge or XT because their glass trans temp is high enough than the temp I need to get it stick to the PEI...
For anybody interested in this bed, David (the one that made the IR sensor) advices to ask Frank to add a black layer on top of the ALU before the PEI coating for the IR sensor to keep working well. I already have two beds ... and I will look at inductive sensors. But if anybody is willing to try ... let us know.
You can already order it in black. I have no idea how he colors them and if it would be possible to add black and then another color if you want it blue or re like you...
I already have a blu and a red (untested) for the bob. The other beds use either manual or ABL on white paper at the corners. I think I have enough beds ... So I will try inductive sensors and in the meantime. Move the sensor as end stop to the bed
Are the beds not coloured by "anodisation"? (An electrolytic process.) As an aside I saw the BCN3d Sigma recently. The bed heater does not even reach the edges of the bed / build area!