PLA Suddenly Jamming Mid-Print

[uncle_bob]

Hi

The current into the stepper is an adjustable number. The motor manufacturer comes up with a number and you set that (or less than that) on the stepper driver IC. Typical numbers are in the 1 to 2A range on the motors. Typical settings are between 50% and 100% of the rating. Normally the stepper driver IC is the first thing to have trouble when current is set to high. People often crank up the drive to check things out and then later forget they did that back 20 weeks ago ....

One thing that *will* heat up the motors and cause jams is trying to extrude to fast. Another thing is a combination of layer height and extrusion settings that force to much plastic into the print. It has nowhere to go and ... you get
back pressure. Eventually the extruder gives up. To much or to little tension on the extruder drive (the part that engages with the filament) can also create the same sort of issues.

Modern hot ends run with cooling blocks that are "cold" at the top end of the unit. If not, you have a fan problem There are other possible design issues in the hot end assembly that could cause the over heat problem. Given how close everything in a normal extruder is to each other, indeed, when one part over heats, it's hard to figure out what is what.

Bob

[Ryuluce]

Hi

The current into the stepper is an adjustable number. The motor manufacturer comes up with a number and you set that (or less than that) on the stepper driver IC. Typical numbers are in the 1 to 2A range on the motors. Typical settings are between 50% and 100% of the rating. Normally the stepper driver IC is the first thing to have trouble when current is set to high. People often crank up the drive to check things out and then later forget they did that back 20 weeks ago ....

One thing that *will* heat up the motors and cause jams is trying to extrude to fast. Another thing is a combination of layer height and extrusion settings that force to much plastic into the print. It has nowhere to go and ... you get
back pressure. Eventually the extruder gives up. To much or to little tension on the extruder drive (the part that engages with the filament) can also create the same sort of issues.

Modern hot ends run with cooling blocks that are "cold" at the top end of the unit. If not, you have a fan problem There are other possible design issues in the hot end assembly that could cause the over heat problem. Given how close everything in a normal extruder is to each other, indeed, when one part over heats, it's hard to figure out what is what.

Bob

I'm going to assume your first point is that I shouldn't need to adjust the current into the stepper motors (which is something I still am suspicious as to whether or not it may be part of my problem).

So, I have tried both reducing the extrusion multipliers and the speed of extrusion, and I only end up with more problems than what I started with. The printer doesn't even start with a good first layer and the whole print is a mess before the third layer.

Also, the Qidi Tech doesn't have the ability to adjust the tension on the extruder drive.