For the last six years I have successfully build my career as an artist, solely on sculptures coming out of the 650. These go for several thousands of Euro’s, so the surface quality has to be impeccable.
Lately, almost 3 out of 4 of my larger pieces come out of the 650 with a very bad surface. This is almost always a section of the piece (in height 3-10 cm) and always facing the front of the machine. In that section, the layers delaminate or are to thin, in any case you see gaps between the layers. These break off during post processing, causing a very ugly end result. See attached an example and a picture which explains the position of the section.
Last week I have conducted a test in which I have filmed the printing of a 15cm figure, standing upright in the printer. The printing took around six hours. In the upright figure I printed, there is a clear line above which layers are delaminating. I have counted the layers up to that point and came to around 700 layers. Exactly at that moment, the printer paused for about ten minutes and it sounded like it was clearing the overflows or fluidizing the feeder. Apparently after that moment, there is to much air in the powder, or the powder isn’t compact enough anymore.
Is there a way to adjust settings so it becomes less likely that this happens? I surely hope so, because my life depends on it. The Dutch distributor says they can not help me. I have also asked for a solution to my problems at 3DSystems themselves, but they have not answered yet.
A number of things could be going wrong:
* clogged powder circulation system
* load cell is beginning to fail (the part that measures how much powder is in the bin)
I think it is most likely the latter problem - your field service should be able to verify that it or is not working correctly.
(or any competent electrical engineer)
Do they have to be gypsum powder (the main component of a ZPrinter 650 powder)? Laser sintered nylon would probably give you a more consistent and better result. I have a ZCorp 310mx and have this sort of problem as the print head is getting old or has a build up of dirt on the active part of the head. The pause you experience on a long job is probably attempting to clean the head, so the station where that happens also needs to be clean. As you know, going to the highest resolution (smallest layer thickness) can help with contours, but in this case it looks more like layers were skipped with low binder infill %, and thus not bonded.
On my unit I sometimes override the binder fluid infill % by 5-8% to attempt to compensate for this sort of thing. It can be done in the custom powder settings. I use a somewhat older interface (the last version from ZCorp) but perhaps this version from 3DS would allow that.
I have see your work before. Congrats on the printer I saw that you did a crowd funding a while ago.What layer height are you printing at? I get gorgeous surface finishes at .08mm finishing the models with a sandblaster is a must… At least we think so to get things to really pop. Here is a print that has no distinguishable stepping and vibrant color.
The main source of issues you will find is generally mechanical. Clean clean clean… Could be your lead screw and if you machine keeps trying to wash its heads then it’s very possible either the head is going bad or it can’t get it clean.
What is the humidity level? We’ve seen this delamination in the layera when humid is above 50℅. Of course this could also be a problem with the print head.
dday
August 19, 2016, 12:34am
6
Hello Eric,
Do you have z650 or 660? I noticed 3D Print software says 660…
That pause that you recorded is normal part of printing cycle - printer stops to empty all overflows which get filled after some time. It usually leaves horizontal mark on the print which is best visible on white parts, and model is indeed more sensitive there. But that is just for a layer or two.
On your recording, can you check if the spread is good during that problematic period? Is the powder surface on the same level over the whole build area when the print is finished?
Have you done feeder fluidizing anytime soon?
I have had similar issue on my Z450 few years ago, but never on Z650.
dday
August 19, 2016, 12:44am
7
A bit off-topic, but your sandblasting cjp models intrigued me. I assume you are blasting green models? Don’t they get damaged? What kind of blaster - abrasive are you using?
I can second you on the cleaning and maintenance - most problems are either bad maintenance or faulty cables (shame on zcorp/3ds for that pogo cable solution)
Thanks,
Stefan
