Extrusion slows down

TAZ 5 with E3D V6 I am having many problems lately. I got my configs back to normal by flashing the firmware but while testing for extrusion calibration I noticed that when it first starts extruding (for say the first 10-15mm) it comes out real fast (like it use to) but then even though the gear is spinning the same speed the extrusion looks like it slows down quite a bit. (the idler is tight).

Now, I have had several bad jams in the E3D and I am wondering it either plastic on the inside of the heat break tube or fine scratches in same would cause this?

I took my entire extruder apart, made sure everything was fine, took the hotend apart to do the same and even put on a brand new nozzle and did the whole test again and it came out the same. If I push the filament in by hand it seems harder to push than it use to with the Hexagon hotend and the Buda style hotend and all this with a .35mm nozzle.

I also stuck a Fluke temperature probe down inside the filament path all the way to the nozzle (the probe is round stainless and the exact same size as the filament so it’s snug all the way down) and it shows at 245 the temperature is low but only by 2 degrees which I think is fine.

Any ideas?

Very strange.

So I should have explained that my prints were very blobby (very easy to see it was heavily over extruding). So, I just kept printing a 20x20x5 box and kept lowering the E steps between each (starting at 800 on the esteps) and low and behold got a perfect print at 500.

This really makes me think something is still seriously wrong. Since I flashed a fresh firmware I am now wondering if it’s hardware related or if it’s is the hotend.

Before all this started, I had prints cracking between layers (I have a heated chamber) and it really felt like under extrusion but during testing on one print the printer froze up and just stopped (never happened before in 2+ years) and would not do anything until I powered it off and on again. Could something be wrong on the board causing steps to be wrong?

I am baffled but I did order up a new E3D hotend (they are on sale right now at Matter Hackers) so I guess that test will tell me.

Here is a photo showing my progression as I turned down the extrusion rate. Note that I did the normal extrusion calibration (extrude 100mm and see it matches) and I had to set the E steps to over 900 to get it to match and the last block in the photo (good print) is with it set to 500. I check my software as well (Simplify 3D and Cura) and both printed almost exactly the same with known good presets.


OK, so I was looking at the perfect print and decided to measure it 20.06 x 20.08 x 2.5… 2.5??? it’s a 5mm high object.

Looking through old photos of settings Z steps/mm = 1599 but when I flashed the firmware it was set to 800 (almost exactly half).

Started testing over with 1599 Z steps and 800 E steps ended in an almost perfect print. Just a little heavy on the extrusion.

Double check which firmware version you are loading onto the printer. 800 steps/mm in Z was standard on our TAZ 1-3 versions. On the TAZ 4 and newer we changed the drive rods, and 1600 steps/mm in Z should be the value on a stock TAZ 5.


My TAZ is a 4 but I did some conversions to make up to date as a 5 mostly the new Hex hotend with extruder but I did not change the drive rods and I used the TAZ 5 firmware so I guess that explains that. No problem I made the change manually back to 800 (had to turn it down to 765 to get height exact) but in the end it looks like everything is printing properly now.