A trick to easily separate part from raft


#21

Hi, guys!

I have Zortrax M200 about month, printed ABS, now tried black Z-Ultrat, first problem - impossible to remove raft from model. With ABS I didn't have such problems.

Any ideas?

I have this problem with Z-HIPS.

Is it an idea of inserting a pause just after raft has been printed and just wait a little and continue? UPDATE : ( Just tried it and does not help a bit )


#22

I have this problem with Z-HIPS.

Is it an idea of inserting a pause just after raft has been printed and just wait a little and continue? UPDATE : ( Just tried it and does not help a bit )

Worth to give it a try. I do something similar (cooling down the last raft layers) when dealing with some 'dangerous filaments'.  :ph34r:


#23

Worth to give it a try. I do something similar (cooling down the last raft layers) when dealing with some 'dangerous filaments'.  :ph34r:

I tried the freeze methode, it seems to be working a bit better but still not easy to seperate.


#24

I had the same problems from the first print.

My problems:

- Raft: was melted to the part or better, the part was melted into the raft completely. Not even a cutterblade helped detaching them. I usually ended up just cutting around the part and keeping the raft hidden under it.

- Stringing: parts with lots of retraction and small printed surfaces (ie. lots of thin pillars) were printed full of strings

- Blobs: all printed parts where full of blobs on the outside. Lucky enough most of them were easy to remove by slightly nudging them.

- Burns: white Z-ABS prints where a nightmare, all looked like dalmatians.

My solution:

- printing Z-ABS at Z-HIPS temps worked fine for me with Z-Suite 0.9.x (not recommended, I used it just to pinpoint the problem on 1 single print)

- not drying the filament (ie. keeping it unprotected around the room) works somewhat

- adding fans to cool the too hot plastic (carefully as too much airflow will cause warping)

- keeping the middle of the perf board (place measured before print) 0.1-0.2 higher than the rest of the plate)

- insulating the extruder PCB from the heat of the hotend and stepper motor***

In my case the temperature of hotend was about 15-20C higher (as read using a thermocouple) compared to what the printer believed it was (read using multimeter on printer's signal line).

*** The extruder PCB has a thermocouple conditioning chip that uses its own temperature reading to offset measured temperature. This chip should have the exact same temperature as the spot on the PCB where the thermocouple wires are attached. Instead the plastic cover right under this chip has a hole positioned so that more heat creeps towards it than it really should.

I measured in my case a temperature difference of ~11C only from this problem. Combined with normal part tolerances and wiring losses, it sums up to the mentioned total of 20C.


#25

Hi

Caesar, could you please post a picture showing how you insulate the thermocouple signal amplifier from heat ? I was thinking about cooling the extruder & pcb with a fan but if you a less intrusive method, I'd be happy to know it.

Thanks 

Laurent


#26

I will take some pics the next time I open it up for servicing.

Basically I just unscrewed the PCB and right in the middle of the plastic support, under the PCB, place a fitting piece of insulation foam. The idea is to get the whole PCB to be heated uniformly. Not to cool it down.

Cooling it will make the problem only worse since the connector for the thermocouple is on the topside (cooled side) and the chip is on the bottom (warmed side).

Remember, you are doing so at your own risk as this change is only backed up by that chip's datasheet.

Follow this guide here: http://support.zortrax.com/extruder-pcb-replacement/

This is the best image I could find online on zortrax support:

2014

Problem-with-extrusion-8.png


#27

Thank you, I understand.

I will first measure precisely temp of my hotend and if it is hotter than expected, I'll will try to fix it too.

Laurent


#28

What about any hints for removing an ABS raft from a fresh print-bed?  This is my first Zortrax and while the print quality is great, the raft removal is TORTURE (fourth print in). 


#29

On removing rafts for HIPS, have to be careful not to smear the material into itself, it's kind of waxy. Once that happens it will not come off cleanly. Also I noticed when things get hot (full enclosure), it's harder to remove the raft.

On ABS from bed, try removing while the bed is heated. I find it easier. Also, has you use the build plate the removal will become easier, fresh plates are the hardest


#30

+1 on ABS raft being easier to remove while still hot, or at least warm.


#31

Thanks, that is MUCH easier. This also has the side panels


#32

"I use pause (software, in Z-Suite) at 0%, so after printing raft - printer stops, raft is cooling down - then I press 'continue printing'..

disadventage? have to remember to put pause in Z-Suite, and have to wait to resume printing after pause.."

How long of a pause is too long?  


#33

It depends on piece size, if pause's too long, piece may separate from raft while printing, but if pause's too short, it may still stick - need to try on your own,

I additionally use second fan now (with on/off button), and I switch it on while printing raft for hard prints.


#34

Thanks Moabie.   I am only having issues on long narrow tall prints.  If the pause play doesn't help Ill move to installing the second fan