First layer issues on large print
- Thread starter igfarm
- Start date
I have been having issues also.
1. The bed is slightly concave. "Had to shim up the middle"
2. The print head keeps coming loose. "I removed and put gasket RTV behind the print head to stabilize it"
3. The x axis had loose hardware "Tighten hardware"
4. The auto home sensor missing springs "had to make springs for it"
5. Bed still has slight deformity "Print 3 layer raft to correct"
1. The bed is slightly concave. "Had to shim up the middle"
2. The print head keeps coming loose. "I removed and put gasket RTV behind the print head to stabilize it"
3. The x axis had loose hardware "Tighten hardware"
4. The auto home sensor missing springs "had to make springs for it"
5. Bed still has slight deformity "Print 3 layer raft to correct"
Since day one I got my gmax, I have been printing model with large surface area and large models. I have been dealing with a lot of problems such as what you described in the first post.
Bed.
It's not flat at all. I had to shim a paper (folded 4 times) on one side near the screw, under the bed. To flatten the bed, it took a lot of trial and error and endless sanding process.
Here's the BEST tool I use for this process:
https://www.amazon.com/gp/product/B0054 ... UTF8&psc=1
After hundred of hours printing, now I know there are one side of my bed that is always bumpy and I just can't do anything about it. The first layer will always be wrong at that area (about 0.8mm too thin at the end).
Extruder height.
Your problem can be caused by extruder height too. I figured out that if the extruder is just slightly too high, it will cause a lot of problems. I chose having the extruder a little bit too low (on bumpy bed area). Using raft will help too if you want.
Temperature and speed.
I found out slower speed and higher temp on first layer help a lot.
Bed.
It's not flat at all. I had to shim a paper (folded 4 times) on one side near the screw, under the bed. To flatten the bed, it took a lot of trial and error and endless sanding process.
Here's the BEST tool I use for this process:
https://www.amazon.com/gp/product/B0054 ... UTF8&psc=1
After hundred of hours printing, now I know there are one side of my bed that is always bumpy and I just can't do anything about it. The first layer will always be wrong at that area (about 0.8mm too thin at the end).
Extruder height.
Your problem can be caused by extruder height too. I figured out that if the extruder is just slightly too high, it will cause a lot of problems. I chose having the extruder a little bit too low (on bumpy bed area). Using raft will help too if you want.
Temperature and speed.
I found out slower speed and higher temp on first layer help a lot.
When I got my gmax I had the exact same issue. Now that I have the heated bed, the new glass is a little better but not perfect... Its nearly impossible to get something 16x16 perfectly flat... but only .05mm can throw this all off.
A few points.
1. The ABL probe can only measure up to .1mm of variation across the entire surface.... Someone told me that, and if true, thats terrible.
2. Most of the spots that were not level were holes, or "spots" not a consistent corner to corner change. So that means the ABL probe never reached in to those spots when it did its grid. Even at 16 pts it never hit them. So you would have to set up 6-10 probe points to make sure you hit those, and im still not sure it would work.
3. If you set it up to compensate for the depressions you will "smoosh" the rest of the first layer a fair amount, which will look bad, but SHOULD work. It has for me.
4. Raft will work, but I hate using rafts. S3D rafts are terrible, and rarely come off right... They have ackowledged a major issue with their raft settings, but I dont know that its been resolved. I HATE how the bottom layer attached to a raft looks. I need nice clean parts.
5. Upping the layer height for the first layer works to an extent, but getting dialed in higher layer height, with extrusion width, etc etc etc is a nightmare. I spent probably 10 hours trying to get it right and never did. Problem is, if you extrude at .3 or .4mm for the first layer, then inside (the fill) never overlaps and looks terrible etc.
I dont know what the answer is,but ive yet to print 1 large print that covers the majority of the bed, and dont have plans to. However id like to know when the need presents itself I have that option. Right now, I dont feel comfortable doing that.
A few points.
1. The ABL probe can only measure up to .1mm of variation across the entire surface.... Someone told me that, and if true, thats terrible.
2. Most of the spots that were not level were holes, or "spots" not a consistent corner to corner change. So that means the ABL probe never reached in to those spots when it did its grid. Even at 16 pts it never hit them. So you would have to set up 6-10 probe points to make sure you hit those, and im still not sure it would work.
3. If you set it up to compensate for the depressions you will "smoosh" the rest of the first layer a fair amount, which will look bad, but SHOULD work. It has for me.
4. Raft will work, but I hate using rafts. S3D rafts are terrible, and rarely come off right... They have ackowledged a major issue with their raft settings, but I dont know that its been resolved. I HATE how the bottom layer attached to a raft looks. I need nice clean parts.
5. Upping the layer height for the first layer works to an extent, but getting dialed in higher layer height, with extrusion width, etc etc etc is a nightmare. I spent probably 10 hours trying to get it right and never did. Problem is, if you extrude at .3 or .4mm for the first layer, then inside (the fill) never overlaps and looks terrible etc.
I dont know what the answer is,but ive yet to print 1 large print that covers the majority of the bed, and dont have plans to. However id like to know when the need presents itself I have that option. Right now, I dont feel comfortable doing that.
I too have been fighting bed level issues on my printer. So bad that gCreate sent me a new AL bed assembly in an effort to correct it. In the end, the problem was actually that the extrusions the bed is attached to were far out of adjustment.
I suggest you clamp a dial indicator to your X axis extrusion, zero it on your bed surface and move the bed to its extents. Mine was running out up to 0.035 inches or 0.89 mm. If you notice the bed running out more that 0.010 inches or so, I would recommend removing the print surface and AL bed plate. Check the run out directly on the extrusions. If they are not within 0.010 inches, adjust the openrail rollers per the manual and tighten or loosen the screw that holds the wheels to the 90 degree angle bracket. It is the screw that has a nylon spacer.
Also, throw away the plexiglass print surface that comes with the printer. Replace it with glass. I used double strength window glass and found it to be much flatter than the plastic. I mounted it to the bed with a fender washer under the glass and the stock hold down washer on top. I am using blue tape at the moment but, if the printer proves to be reliable, I will invest in a heated build plate with PEI installed.
I suggest you clamp a dial indicator to your X axis extrusion, zero it on your bed surface and move the bed to its extents. Mine was running out up to 0.035 inches or 0.89 mm. If you notice the bed running out more that 0.010 inches or so, I would recommend removing the print surface and AL bed plate. Check the run out directly on the extrusions. If they are not within 0.010 inches, adjust the openrail rollers per the manual and tighten or loosen the screw that holds the wheels to the 90 degree angle bracket. It is the screw that has a nylon spacer.
Also, throw away the plexiglass print surface that comes with the printer. Replace it with glass. I used double strength window glass and found it to be much flatter than the plastic. I mounted it to the bed with a fender washer under the glass and the stock hold down washer on top. I am using blue tape at the moment but, if the printer proves to be reliable, I will invest in a heated build plate with PEI installed.
We have found this issue typically can be solved with slicing changes. I say this because we have spent nearly 2 years on this problem since many of our printed parts required a clean finish.
What's happening relates to heat and the plastic expansion/contraction especially on a cold bed. You will notice when printing large flat objects, the edges seem to stick fine and it's the center that is not sticking. If you watch it very closely you will see the hotend is pressing the plastic down on the surface however the adjoining plastic is actually causing it to pull up. It looks like the adjoining plastic is cooling causing the new, hot, plastic to curl up towards it.
Anyway, we have solved it by making the 1st layer much thinner in width. Maybe 50% or less but also make the 1st layer height 200%-300% or more. This causes the adjoining layers to be closer together and a lot more plastic is pushed out. You can also experiment with slowing down the first layer, or speeding it up, depending on the shape of your object. using this method we have been able to print copy paper sized flat objects with almost no issues. Remember the slicing settings included with our profiles are "general" settings and every print is different.
We have also found that acrylic produces a near perfect surface finish when compared to buildtak or painters tape. We printed all of our old LCD screens on acrylic and the surface was clean especially when using carbon fiber filament.
What's happening relates to heat and the plastic expansion/contraction especially on a cold bed. You will notice when printing large flat objects, the edges seem to stick fine and it's the center that is not sticking. If you watch it very closely you will see the hotend is pressing the plastic down on the surface however the adjoining plastic is actually causing it to pull up. It looks like the adjoining plastic is cooling causing the new, hot, plastic to curl up towards it.
Anyway, we have solved it by making the 1st layer much thinner in width. Maybe 50% or less but also make the 1st layer height 200%-300% or more. This causes the adjoining layers to be closer together and a lot more plastic is pushed out. You can also experiment with slowing down the first layer, or speeding it up, depending on the shape of your object. using this method we have been able to print copy paper sized flat objects with almost no issues. Remember the slicing settings included with our profiles are "general" settings and every print is different.
We have also found that acrylic produces a near perfect surface finish when compared to buildtak or painters tape. We printed all of our old LCD screens on acrylic and the surface was clean especially when using carbon fiber filament.
Hey Guys,
I have the exact same problem but with my heated bed. I have changed the setting of the first layer to 300%-250% layer height, 45%-20% layer width, and 45%-20% speed. Even though I have done this I'm still getting issues when it comes to the wavy middle section of the print. I'm starting to think that I need a surface on top of my heated build plate but I want to work a project ASAP so was wondering if there is either a way use the acrylic bed that came with the printer and put it on top of the heated build plate or if there's another option in Simplify3D or a way of updating the BLTouch sensor to tell the printer that the bed is lower in that specific area.
Thanks for reading!
I have the exact same problem but with my heated bed. I have changed the setting of the first layer to 300%-250% layer height, 45%-20% layer width, and 45%-20% speed. Even though I have done this I'm still getting issues when it comes to the wavy middle section of the print. I'm starting to think that I need a surface on top of my heated build plate but I want to work a project ASAP so was wondering if there is either a way use the acrylic bed that came with the printer and put it on top of the heated build plate or if there's another option in Simplify3D or a way of updating the BLTouch sensor to tell the printer that the bed is lower in that specific area.
Thanks for reading!