irregular layers

I have started to get some irregular layers in my prints. I am printing with a .3mm layer and they are not even on the face, The layers will run two even and then one indented a small amount all through the prints. If I go down to .2mm per layer it comes out to 3 layers even and one that is indented a small amount. I have a MendelMax 1.5 using precision screws. There is no discernable play in the rods at all. I have used Pronterface, Reptier, and S3DCreator and the results are always the same. The prints with the .2mm layers is alot better that the .3mm layers, and I even tried .4, which was better than .3 also. I am at a loss. I can not get a flat face on my prints. Suggestions will be greatly appreciated.

Milt

A picture would help greatly. Do your Z screws wobble at all during layer changes?

I am at work right now. No, my z screws are not swobbling at all, I have installed bearings on the tops.
I will get some pics when I get home again.

Milt

mondo50m Wrote:
-------------------------------------------------------
> I have installed bearings on the
> tops.

That could be your problem. If your Z screws aren't perfectly straight and you over-constrain them, they will cause banding.

perhaps a motor shaft is no longer centered? there also is the controversial layer precision adjustment you can do in firmware. which takes z steps and rounds them to the nearest step.

Can not wait to get home and check out these suggestions.

Milt

I think I may be having an issue with my Extruder temperature. I need to go down to approximately 190c to get a really good print with ABS. I have tried it with all of my colors. I will be getting a new thermister soon.

Milt