PLA Lamination Problem

When I print the 15mm cube in PLA, the layers don’t merge. They just seem to be individual layers loosely attached to each other. My 15mm cube looks like a stack of cards. I have tried Extruder Temps from "190 1st layer/180 other layers" to "210 1st layer/205 other layers" with no noticeable change. I tried shutting off the fan, but then none of the layers stuck and all I got was a wad of plastic. I'm printing onto blue painters' tape.

I have checked and re-checked the Z height (allows a piece of paper between, but not a heavy business card).

I have a Robo 3D PLA & ABS w/Heated Bed. It has a fan and (borosilicate?) glass bed. I don't intend to print in ABS for a while, I want to get PLA working.

Settings:

Filament Diameter 1.75
Extrusion Multiplier 1
Extruder 1st layer 210 C Other layers 205 C
Bed 1st layer 0 Other layers 0

Layer Height 0.3
1st Layer 100%

Perimeters 4
Generate extra perimeters when needed is checked
Solid Layers Top 3 Bottom 3

Infill 0.5
Fill Pattern Rectilinear
Top/Bottom Fill Rectilinear

Fan Speed Min 35 Max 100
Bridges Fan Speed 100
Disable fan for 1st layer is checked
Enable fan if layer print time is below 60 seconds
Slow down if layer print time is below 30 seconds

Minimum Print Speed 10 mm/second

 

Hi Dennis,

First check the tension on the belts. It should make a low guitar hum when you pluck it. If it is too loose it could be skipping.
Second try using 195C for all layers, Fan always on 100%, and 2 perimeters.

 

I will check and tighten the belts if they are loose; but intuitively, the problem would seem to be a Z axis problem since I have vertical de-lamination. The cube's X and Y dimensions seem pretty square.

Otherwise I thought it might be temperature or extruder settings. I tried a fairly wide range of temperatures and other posts have mentioned that concave or convex sides on the 15mm cube indicate under and over extrusion. I don't seem to have that problem.

I will try using 195C for all layers, Fan @ 100%, with 2 perimeters. I think that I will also try a little lubrication on the Z axis threaded rods.

 

Thanks. I will add the skirt and check the flow (once I check my belts, etc.).

 

I spent quite a bit of time making adjustments. The Y-axis belt was quite tight. I tightened the X-axis belt. I spent a lot of time trying to adjust the Z-axis. I have adjusted it as low as possible without having it in contact with the bed. I still see the same problem.

The skirt is so small it is difficult to tell if it is flat or not. I'm printing with the blue PLA (that came with the printer) onto blue painter's tape. The first layer sticks and looks good.

The part of the problem that I can't wrap my head around is while the home position of the Z-axis would have an effect on the first layer, how can it have an effect on subsequent layers? In other words, I'm wondering if the Z-axis steps are wrong.

At .3mm per layer, the 15mm cube has 50 layers. Even if the first layer is off, how can that have an effect on the 40th layer?

 

I checked the Z-axis smooth rods and both are solid. Their mounts on the baseplate are not cracked or broken.

Is it possible that Repetier-Host (Mac) is not commanding the correct Z steps?

I thought that I would try the new MatterControlSetup-1.0.5 software that Robo 3D has posted. I want to see if I have the same Z-axis problem. Anybody have any experience with the new software?

 

I was having a very odd issue with MC that may be the same thing you are seeing. I would adjust my Z height to the perfect setting but the first layer would start way too high. I am not sure what in the world was causing this, but after switching to Slic3r for slicing then dropping the Gcode into MC it has fixed the problem. Maybe something to look into.

 

Funny, I literally just had this problem 10 minutes ago. I've been experimenting with different programs to see what will print a part I need best, which so far is MC other than the initial height problem. I just sit next to it until it starts and manually adjust the rods once it begins and it comes out fine.

 

Try slicing with Slic3r then dropping the Gcode into the print cue. This solved it for me; adjusting the threaded rods is a very stop-gad solution and shouldn't be practiced as the norm.

 

First thing I think of is printing at .3 layer height is a lot if you are looking for a nice print. Try .1 layer height.

I'm working on some problems with my printer too. One thing to check is how true your z axis threaded rods run. The ones on my machine were running out a lot. You can take them out and roll them on a flat surface like glass or a really flat table. If you see that they are bent you can try and bent them just a little at a time to true them up. Also the couplings that attach them to the motors should be checked to see if they run out a lot while on the motors. Some people say it doesn't matter. That's just not true. The better things run the better the machine will work. Robo3d can send you new parts if any of the couplings are running out a lot. I made solid ones on my lathe that run dead true. This helped big time in getting better prints.

Also just because the z axis smooth rod stabilziers seem good doesn't mean they are. Look at the closely. If you see any light lines where the round part of the stablizer meets the square part that could mean there is a crack on one side of it. Removing it and really looking at it closely is the best way to check for cracks.

Another thing I see on my machine is that it uses 5/16" smooth rods instead of 8mm. Where the head rides on the x axis it is easy to feel the play in the bearings. This has to be causing poor printing. I am going to try and change the rods to 8mm ground ones. The ones in the machine measure .311 and 8mm is .315 You can't have .004 play in bearings and expect it to work right.

 

This is what is happening lately. I am at a loss of where the problem is and how to fix it.

I am also concerned all the screws on this thing are made of wax. They are so strippable. I feel like I need to replace all screws and lock nuts.




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I'm at a loss too. I know that just about everything on my machine needs work. I hear that people are running their machines at around 30mm per second when printing. This could be due to so many parts being put together wrong and not making the machine strong enough to take the quick movements. Support at the top of the rods should be built into this machine. I will do that once I get the 8mm rods installed and have it printing.

The other day I looked at the z limit switch and saw that the screws that mount the switch to it's mount were stripped out and not holding it in place. I drilled out the holes in the bracket and used 2-56 screws and nuts to mount the switch to the mount. This explains why I had such a hard time setting the z height with a sheet of paper over the bed. Now it should stay set when I adjust it.

 

Peter, are you stripping the screw heads with the screwdriver? If so you are simply using the wrong size Philips screw driver for the particular screw. Usually use a larger size Philips driver than you would think. Using too small a driver will strip the head. You will need two Philips driver sizes to handle most of the screws on the machine.

If you are talking about the screw threads themselves I really don't understand how you can strip them. The quality of the screws used in any of the Robos that i have seen are just fine.

 

The bed screws are weak. I did manage to get the bed off and on using a larger Philips screw driver as you suggested. Using the one supplied with the printer is not good.


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Sorry Peter, If you use the wrong size driver any screw head will strip. The screws are not weak.

 

I understand what they are saying. These screws strip much more easily than most other screws I've dealt with. Could just be a cheaper alloy or something but it is imperative that you have the right driver size or you are literally, wait for it...... screwed! (get it?)

 

Sorry it has been so long since my last post. I finally tried the new MaterControl software for the Robo 3D (downloaded from the Robo 3D site). Even though I was printing with PLA, it heated the bed to 60 degrees C. The results were sooo much better. In the picture, the new cube in on the left, my original cube is on the right. I did note that it printed layers at .2 rather than .3 that I was trying before. I had been using blue painters' tape on the bed, which works well; but the heated bed seemed to melt it. I then tried to print with nothing on the bed, but the PLA didn't stick. So I plan to pick up a glue stick to try.