Heavy parts & Platform Deflection?
Posted: Sat Mar 18, 2017 2:17 pm
I recently printed some big parts - .65 kg of PETG. Almost 8" OD and 4" tall. The first layer is consistent across the part so I'll assume the bed is level. The platform is bare MIC6 aluminum, so it should be flat. Layer thickness was .25mm. Dimensional accuracy is important on these parts in all 3 axes.
On the finished part X and Y dimensions look great. On the Z axis I get about .9mm, .035" of taper from one side to the other.
My first though was that the weight of the part was causing the bed to deflect. It doesn't take much force on the bed plate to deflect the platform. One would think, however, that the minimum deflection would be near the screw and maximum deflection would be at the far side of the cantilever opposite the screw. The one part I still have on hand shows the opposite. The tall side of the part is near the screw and the short side is opposite the screw.
I saw the same sort of taper on ABS parts of similar size, but much lighter, so I'm not convinced that it's weight, but with the Z-Axis rail arrangement, I haven't figured out how this could be an alignment issue.
I'll be working on finding the cause of this. Has anyone else ever looked into this, or do you get large, heavy parts that are consistent in the Z-Axis?
On the finished part X and Y dimensions look great. On the Z axis I get about .9mm, .035" of taper from one side to the other.
My first though was that the weight of the part was causing the bed to deflect. It doesn't take much force on the bed plate to deflect the platform. One would think, however, that the minimum deflection would be near the screw and maximum deflection would be at the far side of the cantilever opposite the screw. The one part I still have on hand shows the opposite. The tall side of the part is near the screw and the short side is opposite the screw.
I saw the same sort of taper on ABS parts of similar size, but much lighter, so I'm not convinced that it's weight, but with the Z-Axis rail arrangement, I haven't figured out how this could be an alignment issue.
I'll be working on finding the cause of this. Has anyone else ever looked into this, or do you get large, heavy parts that are consistent in the Z-Axis?