baron
Posts: 9
Joined: Fri May 09, 2014 8:07 am

Calibrating Process/Profile for good prints

Fri May 09, 2014 9:15 am

Hi,

I need to calibrate my profiles to get more out of my prints. I'm new to S3D and also fairly inexperienced in the 3D printing field, so I need someone to point me in the right direction.

What I want to achieve
- Prints that accurately comes out the with the same size as the stl file. ie, a 20mm box should be 20mm or very close to when printed.
- Printed parts should fit together when properly designed to
- Good general print quality (correct retraction/correct amount of extruded plastics/correct travelling distances/etc)

Problems I have right now in S3D
- Extruded lines aren't properly merged together, so either they offset to much or it extrudes to little plastics (I guess the latter?)
- If I print a 20mmBox, the corners where the layer starts its perimeters gets a little blob at every layer. Is it due to too little retract? (I have disabled deprime in sailfish)

I have a pretty good understanding of what most of the settings do, but I'm not sure where to start.

I tried to solve, what I thought was to little plastics extruded (spacing between lines when printing with 100% infill) by trying printing boxes with an Extrusion Multiplier of .90, 1.00 & 1.1. Which I think is pretty big increments, but didn't see much of a difference really.

FYI, printing on a Makerbot Replicator 2 with sailfish installed. Prints come out very good looking in makerware, and I've printed about 600h on it. It was actually when I started to looking in to calibrating it to better print correct dimensions and properly print parts that fit together I moved to S3D, to be able to, in a more convenient way, modify advanced print settings.

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jimc
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Location: mullica, nj
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Re: Calibrating Process/Profile for good prints

Sat May 10, 2014 8:43 am

there are multiple calibration objects you dan download from thingiverse and print. for your extrusion, the multiplier is a fine tune. the big thing first is to be sure your filament dia is set correctly. you need to set that then tune the multiplier for every roll of filament. you need to get that right first. then tune for accuracy and blobs. the blobs can be made to go away using the coasting settings and a small neg restart distance if needed.

baron
Posts: 9
Joined: Fri May 09, 2014 8:07 am

Re: Calibrating Process/Profile for good prints

Sat May 10, 2014 11:30 am

Thank's for your suggestion. I'm in the middle of printing loads of objects with different settings for extrution multiplier. What I don't fully get my head around is that I don't get very different results when printing the same objects with a multiplier between 0.90 and 1.10, my guess is that that should be a pretty big increment and show a pretty big difference visually on my prints.

I am measuring my filaments thoroughly with a calliper and make sure to set that in my profile before starting my calibration. I have now tried two different filaments when I went out of ideas why I'm not able to improve my results with S3D. Everything looks perfect with other slicers. So it's clearly something I'm missing here

To save time I print 3-5 small boxes of 20x20x10mm with different extrusion multiplier settings. I'm confident that I correctly choose different processes for the different boxes on my bed. But the results seems VERY similar on all boxes. Maybe I should try printing them one at a time with different settings instead. To eliminate user error on my part doing the settings and/or bug in the software.

Thanks for the coasting tip, it should probably fix my blobs on the end of the loops.

PS, I printed a "1 shell wall" with 0.90 as extrution multiplier and measured it, it's exactly 0.4mm thick, which is exactly what S3D expects in Extrution widht. And it also matches my nozzle diameter. Doesn't that mean that the extrusion multiplier is good if filament diameter is correctly entered?

baron
Posts: 9
Joined: Fri May 09, 2014 8:07 am

Re: Calibrating Process/Profile for good prints

Sat May 10, 2014 12:43 pm

I will report a bug to the support if they don't answer here during next week.

The behaviour is as follows.

If I print tree boxes in the same print with each of it's own process settings, exactly the same except Extrusion multiplier. They come out the same.

If I print on single box at a time with different Extrution multiplies the settings work as expected.

quite a shame, I've spent about 10-15 hours on this. :oops: Feel a bit stupid that I didn't try earlier to print on at a time.


Other settings seems to work as intended, for example, when I print two boxes at the same time, one with 100% infill; and one with no infill/no floor/no roof/different brim settings etc, they behave as intended.

Well, my calibration will continue now, I am going to print a few more boxes and I'll get back if there's more stuff I can't figure out. Any additional tips are welcome

JoeJ
Posts: 1436
Joined: Sun Feb 16, 2014 10:52 am

Re: Calibrating Process/Profile for good prints

Sat May 10, 2014 3:03 pm

Are you saying that you don't think this is working correctly just based on how the prints look? Or have you actually looked through the gcode files to verify that the extrusion multipliers are wrong. I just tested this on my own a few times and I don't see anything wrong. I'm looking at the actual files though. As you said, it can be hard to actually see the difference in the prints, and I would hesitate to bug the support guys just based on looks.

baron
Posts: 9
Joined: Fri May 09, 2014 8:07 am

Re: Calibrating Process/Profile for good prints

Sun May 11, 2014 4:03 am

JoeJ wrote:Are you saying that you don't think this is working correctly just based on how the prints look? Or have you actually looked through the gcode files to verify that the extrusion multipliers are wrong. I just tested this on my own a few times and I don't see anything wrong. I'm looking at the actual files though. As you said, it can be hard to actually see the difference in the prints, and I would hesitate to bug the support guys just based on looks.
Well, the "look" is very convincing, will post pictures late today when I get hold of the printed examples.

But in short.
Printing 3 boxes of 20x20x10 mm in one print with individual processes, one with Extrution multiplier 0.90, one with 1.00 and one with 1.10 (yes I know, big increments)
ALL of the tree boxes are under extruding alot

Then printed a single 20x20x10 mm box with 1.10 as Extr. Multiplier, and it's over extruding alot. Have now found that an extrution multiplier of about 0.95-0.98 works very good for my bot with the two PLA-filaments I've been trying with.

I have not looked through the Gcode, not very experienced with Gcode. What variable controls the "extrution multiplier", should be listed in the code during every travel move between the boxes on a continous print I guess, so if I know what to look for I could check it out.

Festus440
Posts: 77
Joined: Wed Aug 07, 2013 8:38 pm

Re: Calibrating Process/Profile for good prints

Sun May 11, 2014 11:20 am

I mostly print parts that need to fit together (or mate with existing metal parts). So at times I need both accurate inside and outside dimensions.
One feature I would really like to see in S3D is an "Inset" function like Kisslicer.
Inset allows you to shrink the thickness of walls slightly. That allows you to set your extrusion parameter for best surface and adhesion. Then using a combination of scaling and inset you can get accurate inside as well as outside dimensions.

laird
Posts: 103
Joined: Wed Sep 18, 2013 1:20 pm

Re: Calibrating Process/Profile for good prints

Mon May 12, 2014 12:35 am

Festus440 wrote:I mostly print parts that need to fit together (or mate with existing metal parts). So at times I need both accurate inside and outside dimensions.
One feature I would really like to see in S3D is an "Inset" function like Kisslicer.
Inset allows you to shrink the thickness of walls slightly. That allows you to set your extrusion parameter for best surface and adhesion. Then using a combination of scaling and inset you can get accurate inside as well as outside dimensions.
Interesting, I always do this in the models, leaving a gap of (typically) 0.4mm between mating parts, so that when printed, the surface texture leads to a smooth fit. That's how I'm used to working in CAD - you spec in a gap based on the material and the manufacturing process.

Generating a model that has no gaps, then using slicer configurations to generate the gaps, would be less work, certainly. What slicers can do that? It might be worth trying out.

baron
Posts: 9
Joined: Fri May 09, 2014 8:07 am

Re: Calibrating Process/Profile for good prints

Tue May 13, 2014 1:12 pm

Yes, you obviously have to either make your model with a slight difference to be able to make the parts fit. But, for example on my printer before I calibrated my print profile in makerware, inner dimensions where off by about 300 microns and outer dimensions where off by about 200 microns. That much difference work hard against you =)

So the calibration is more to get it more precise, or as precise as possible. Because if I make models for my self with my "bad callibration" accounted for, if someone else print my parts with better calibration the hole will be to big. Same thing other way around if I download others parts.

Festus440
Posts: 77
Joined: Wed Aug 07, 2013 8:38 pm

Re: Calibrating Process/Profile for good prints

Tue May 13, 2014 2:23 pm

laird wrote:Interesting, I always do this in the models, leaving a gap of (typically) 0.4mm between mating parts, so that when printed, the surface texture leads to a smooth fit. That's how I'm used to working in CAD - you spec in a gap based on the material and the manufacturing process.

Generating a model that has no gaps, then using slicer configurations to generate the gaps, would be less work, certainly. What slicers can do that? It might be worth trying out.
Yes of course. The parts I'm designing are also intended to be mass produced and already have clearance for the mating parts built in and usually include draft that would be required for doing an injection molded part. However I prefer not to have to modify my models in order for the dimensions to come out correctly from the printer. It seem like whenever I get the outside dimensions and appearance to what I like, the inside dimensions run small. Now I could just play with extrusion widths and flow, but as I mentioned I like the "Inset" function that Kiss has that shrinks wall thickness slightly. A similar function in Simply 3D would be a great addition.

At work I'm spoiled by having access to a six figure polyjet printer that has a +/- 0.001" printing accuracy. I certainly don't expect anything like that from my home printer, but if I can get parts to fit together without modifying my model that Is preferred. Of course I cant say I haven't printed an occasional Yoda head :D

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