First Layer Woes

[TimBobTastic]

Hi

We have recently received an Orion 3D printer and are having a few problems.

The machine has been set up, We have checked level and Z height and when we printed blinky, it looked exactly like the sample we received with the machine

We then connected the machine to a PC so we could print our own parts, but as you can see in the attached file there is always a problem on one side of the machine (see image of 90mm diameter component).

The image shows the bottom layer of a thin print, as you can see, one side is nicely formed and fused and the other is very open… the top side is fine.

We have found better results using Slic3r compared to CuraEngine.

As stated above the following has been checked a number of times
• Z Zero
o I have checked this both using the on board controller and Repetier
o Both are within 0.1mm of each other

• Head Level (using slip gauges at the co-ordinates specified in the user manual)
o This has been checked a number of times, again using both the on board controller and Repetier
o Both give variations of between 0.1 and 0.2mm

• Head Level (at 0,75 0,-75 75,0 and -75,0)
o All readings are within 0.1mm

The components are dimensionally correct (within 0.05mm)

We have also tried a number of different fill patterns which all give the same results, one side filled as expected the other side very open as shown it the attached photo.
All prints are sticking to the table well.

I am not sure what else to check....

Using PLA, 200°C Head, 70°C Table, 0.35mm first layer 0.2mm other layers, feed rate 25mm/s (same results at 30mm/s)

The top surface of the build is very good, no gaps, pretty much as expected....

We have tried a number of different shaped and sized components and the problem is always on the same side of the table.....

Thanks in advance
Tim

[Mac The Knife]

I don't see where you tried to recalibrate the towers, Did you?

[TimBobTastic]

Hiya Mac
Thanks for the response

I have not worked through the tower calibration fully. I have checked the distances using engineering slip gauges at the XY positions defined in the tower calibration code and found them all to be with in 0.1mm of each other 5mm from the table (measurements between 4.92 and 5.01) (I doubt this level of certainty is achievable visually). Is my process much different from the tower calibration specified?

I also cross referenced this with a check along the X any Y zero lines (plus and minus 75 in each direction) with similar results.

The machine is at work and I am not in the office today (working from home)... I will work through the tower calibration on Monday and report back, it is more than possible that I have missed something...

Thanks for the input

[mhackney]

Firstly, please read the Start Here link in my signature.

Here's what I see:

1) calibration is not good. The thin first layer at the bottom and fat layer at the top is indicative of this. Want to verify? Simply rotate the part in Slic3r - say something like 90° and reslice and print. You'll see the same poor first layer but rotated 90°. This indicates a calibration or mechanical problem

2) The gap in the first later in the middle of the fill (you can see it well at the top) is something I've experienced for years with round parts in Slic3r. I have a box of parts here with that gap. If your calibration was good, you would see that circle the entire part. I'm surprised you don't see it on the top surface as it always shows up there for me too. Can you post a photo of the top please?

3) I also see improper retract or wipe. On the far right 5 perimeters in from the edge you see a triangular gap with an "L" end piece of extruded filament and a hair trailing down. It looks like you are printing perimeters outside in and this was the ending spot.

[TimBobTastic]

Thanks Everyone

I have calibrated the towers as suggested ... The first layer is printing now and looks MUCH MUCH better... As soon as its off the machine I will send some photos of the top and bottom faces...

Tim

[TimBobTastic]

Photos....

The first layer is very much improved... some open areas, but generally much better.

I have a few gaps in the item, but it is relatively thin (1.2mm), is this to be expected or can this improved upon.

Thanks for everyone's input.

[mhackney]

Now I see:

1) calibration is pretty good, the first layer thickness is consistent across the part and looks about right when I zoom in all the way.

2) The gap in the first and top layers is something I've experienced for years with round parts in Slic3r. Now you see the gap al the way around and where it intersects features like the through holes, it is a little wonky too. The top layer actually looks pretty well filled looking at the filament beads away from these areas. I struggled with Slic3r for a long time over this problem. My fly fishing reel parts are very similar to this ring. You can really see it in this photo of my very first reel prototype that was sliced with Slic3r:

[img]http://mhackney.zenfolio.com/img/s9/v96 ... 5104-3.jpg[/img]

I do have a way to improve this problem but it may not be suitable for all parts without editing the gcode. First, let me tell you a few things I've tried:

a) Since I designed my parts I could redraw them to be even multiples of my nozzle width (0.40mm). That did not help, in fact it is worse at even nozzle width increments. I also tried an odd number, .33, .25 and .5mm increases. All leave that slicing artifact. So, the slicer is doing what it does regardless of the geometry dimensions.

b) changing nozzle width in the slicer to tweak it had marginal effect.

c) changing flow rate negatively affected the whole part

I did a lot more but I don't want to write a book about it here. So, what I did that almost worked...

Increase the number of perimeters to a high enough value that Slic3r does not get a chance to use infill on the first or top layer. In many cases this gave me good surfaces. However, it does result in a 100% solid part and that might not be what you want. In that case, I "slice twice" and substitute the good top and bottom layers from the 100% perimeter gcode into the normal gcode.

3) I can' see any evidence of improper wipe or retract now but I do see a piece of debris in the first layer at about the 4 o'clock position. Clean your build surface well!

[Khalid Khattak]

mhackney...you are great... my print seems to be very soon like yours ...thanks for the tips...