Hi I am a beginner at this and hope someone can help.
I purchased recently a Formbot T-Rex 2 printer. Early on in the assemble process I’m afraid I hooked up the motor for the cooling fan on the electronics box backwards and it burned the fan motor. I was unfamiliar and hoped that the box would be cool enough if I just left the cover off. The print attempts slipped badly. I replaced the fan and was able to make a couple of successful prints, but then the Y direction started slipping again. Finally the driver for the Y direction stepper motor failed. I replaced the driver but my prints continued to slip. A U-tube video for a rep-rap machine showed the need to balance the voltages on the drivers. The voltage on the Y drive I replaced was much lower than the others, so I adjusted the voltage to equal the others, around 1.2VDC. I would shut the machine off, tweak the potentiometer and turn the machine on to measure again. The last print did much better, it printed for over an hour before it finally slipped again. Formbot tries to help but they keep telling me the fan needs to stay on. The fan is plugged in constantly, the driver voltage is adjusted. Is there anything more I can look at? Should I change the Y stepper motor? Notice the attached picture is of a test cube someone in the community recommended I print. The Y plane is very rough, and finally the last layers started to slip. The machine is still under warranty, is it time to request them to replace it?
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chanman
December 12, 2016, 3:24pm
2
Check the belts, looks like there is some slippage there. If you can get a replacement but this is something that can be fixed with some playing.
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Thanks for your help. I’ll check/tighten the belts as you suggest. We actually got a much better print last night without slipping. Formbot recommended to clean and oil the guides. After I did the action of the table was much more smooth and it didn’t slip and this was like a 2 hour print. Only after about 75% was done the nozzle hit the work and knocked it off the bed. Formbot recommended I lower the nozzle a little more to get the first layer down better. We think the edge warped a little and raised the piece into the path of the nozzle. Can I ask one more thing, Formbot recommends I use a bed temperature of 55degc with PLA. It doesn’t seem adequate to hold the piece in place. I notice 3D hubs recommended 60-70degc in their troubleshooting guide. I’ve been using 65. When I tried raising it to 68 for this test print it seem later to cause the edge to warp and raise the work a little. What’s best higher or lower?
chanman
December 12, 2016, 10:12pm
4
I have a Makerbot Replicator 2 which does not have a heated bed and have no issues using blue tape on top of the build surface. I also have a sheet of Fleck3D flexible build plate which also does not need heat. I would second lower the head so that a sheet of paper will have “some” resistance to moving when the nozzle is in the Z home position. Get the height first then play with the bed temp.
What type of lube did you use for the slides? I have some silicone grease (clear) that works well, same as the stuff that came with the Makerbot printer. Any other types will breakdown and you will get binding when exposed to heat.
Again I appreciate your comments, thank you. The Formbot people didn’t specify any special lubricant, they just said to put some oil on the guides. I used some white lithium grease I had in the shed. Made by liquid wrench. Think I should change it?it says "does not freeze, melt or run, long lasting heavy duty lubricant. I think I’m going to lower the nozzle by 0.2 mm and lower the bed temperature back down to 165 degrees C and see who that does. I’m getting closer to a finished cube.
Garyg
December 13, 2016, 2:59am
6
165C bed temperature is very Hot.
What material are you printing with?
Oh I’m sorry no, did I write 165? I meant to say 65degC. My age is starting to show and I need to double check what I write. Especially when my phone wants to change what I say
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chanman
December 15, 2016, 4:12pm
8
Lithium is OK. be sure to wipe off the excess, only a small amount is needed.
Once you have leveled the bed to the nozzle, the first layer will be good. Does not explain the shifting, were you able to check the belts?
Yes, the belts are tight. As I say the shifting started after I had allowed the electronics box to run for about 3 hours without the fan. I thought simply leaving the cover off of the box would allow it to be cool enough. I replaced the fan, but my prints started shifting. Later the Y driver failed altogether. I replaced the driver, but it continued to shift. I tuned the driver to the same voltage as the other drivers, and so far now, as far as I know the shifting is not happening. But I haven’t tried any long prints yet so I’m not certain. Right now I am fixing a failed end stop switch. Soon as I get it all back in service I’ll test again.
Thanks so much for getting back to me. I’ll let you know where it goes!
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