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I have a self-built printer, built on the design of the M Prime one. I use Cura and has an unheated bed.

It seems that the extruder isn’t extruding evenly. I have tried to lower the hotend down but it does

not seem to help. Take a look at the added image.

The top part, shows clearly how unevenly it prints. I did manage to print out a piece that turned out fine. Used the finest quality at 0.1. Took forever, so I lowered the quality to 0.2 for my second piece.

That didn’t go so well.

Any suggestion on what I could try to fix this?

printer_1.jpg
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You dont say what your nozzle size is.

First layers are always tricky, you may want to try increasing the first layer thickness, for a 0.4 or 0.5 nozzle try a 0.3mm thickness, and make sure your bed is level.

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What material are you printing with, and what’s the hotend’s temperature?

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Hi Frode,

It seems like your material is not sticking to the bed properly.

I;ve got a few suggestions:

- If you are using auto bed levelling, try levelling it manually

- Clean the bed properly before printing

- Perhaps try to heat the bed a little using something like a hairdryer

- Cover the bed with blue painters tape, or use glue stick

Let me know if one of these things worked, and/or if you need more help!

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Withe extruder off the bed lets say at 50mm does it extrude cleanly and smoothly if you tell it to push out 50mm? You did calibrate the exturder? Do you have the correct thermistor table selected?

Here is a link to a site that talks about print issues, it’s by Simplify3d but the principles are the same.

https://www.simplify3d.com/support/print-quality-troubleshooting/

Hopefully this helps

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The nozzle is 1.75 x 0.4mm.

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I checked calibration on the extruder, its acurate.

Great website! definitely bookmark worthy.

From that I can tell that my printer is not extruding enough plastic. When I help it along by pushing in the filament, then the layer is as it should be. Will check this out tonight.

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PLA 1.75mm, hotend temp is 210 C

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Hi, there are several possible reasons for your blotchy layer:

Try tightening the extruder tensioner. The extruder may not be gripping the filament well enough.

Reduce your print speed to around 50mm/s.

Although your machine may be quite new you may have a clogged nozzle.

Your nozzle temp may be too low. You should be around 180 - 210 C for PLA.

Make sure your build bed is level and your Z stop is adjusted properly.

Add a heated bed. PLA adheres much better with a bed temp of 50 - 60C.

Your layer thickness should not be less than 50% of your nozzle diameter.

Double check your slicer settings for the 1st layer.

I hope this helps. Best of luck.

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Hi Frode,

seems like your platform is too smooth for PLA to stick.

Even heated, some surfaces do not work well.

Try double sided tape or hairspray.

good luck!

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Your two close. Start with a thicker first layer

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Also make sure you z axis height is properly calibrated as well as your extrusion feed rate

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If you need to push along filament then something is adding pressure onto the motor and preventing that from working properly. That might be anything from a clogged nozzle, too low extruder motor current, not enough tension on the extruder gearing so it can’t grip the filament, filament grinding, too low temperatures on the nozzle (wrong thermistor maybe), or a nozzle too close to the heatbed (although that looks differently) As suggested before try extruding mid air and see what can fix your problem.

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Hoi,
looks like that the 1st layer is too near to the bed.
Try to level the bed wit the built-in option of CURA.
What Nozzle diameter do you use and what kind of Fila ?

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I had a similar issue with a printer I had built. Turned out I had a partial clog. Try to clean your nozzle and see if issue goes away.

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It looks to me like your extruder is clogged. With the extruder away from the bed run 100 mm of filament through it with 215C temps at a faster speed than you can print. I use Simplify3D so don’t know how to do that in Cura. If the filament comes out wavy and/or sticks to the tip, you are still clogged. Clean the tip’s surface with a towel and extrude another 100mm. Keep doing that until the filament comes out straight and not wiggling around as it comes out of the tip.

I

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One more possible variant is in hot end fan. I had the same issue when not cooling a hot end printing PLA

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Great success. I increased the extruder motor current. Increased the flow rate a bit and made the top and bottom a little thicker. Looks like it worked. Thanks all for your help.

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I did a test to see if the bed was even. Found out that it varies from 0.1 - 0.5mm. That explaines why it has so much problems on the first layer. I use aluminum plate, think its 3mm thick. Have now ordered a glass plate, and are going to mount it above the alu plate with adjustable screws to make it as level as possible. The test semicube object I’ve been using as been small enough so that its not effected by the “bumps”. But when I tried something bigger it fails completly.

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more pics of the printer would help… either your extruder drive gear is slipping or your temperature is too low. I print all the time at 0.24mm and the prints are fine. 0.1 is only needed for very small prints or prints with too many details…