Jump to content
Ultimaker Community of 3D Printing Experts
joel-mercier

Rivets reproduction

Recommended Posts

Hello forum,

I am Joël, living in France and using a Ultimaker2 that I bought a year ago. until now I didn't print much but now, I have more time to spend on it.

Right now, am trying to print an Iron bridge structure but I got a problem in between the rivets. A line of plastic appears. Is it possible to avoid it?

The diameter of the rivets is 0,4mm. I thought that is could be coming from the "Z hop when retracting" parameter that I've set to "3" and the "minimum travel" parameter at 1,5mm but it doesn't change anything... Is there any way to improve it?

image1.thumb.JPG.950e99e4730f029a7f1538ea49a92e03.JPG[/media-thumb]

Thanks in advance for your answers

Joël

image1.thumb.JPG.950e99e4730f029a7f1538ea49a92e03.JPG

Share this post


Link to post
Share on other sites

Is it actually retracting between each one? if not then you will need to reduce the minimum travel and the minimum extrusion before retracting.

As the rivets are rounded and small adjust the retraction minimum extrusion and travel amounts as small as possible. You can look in layer view to check to make sure its retracting between each one. If you make the amounts to small it may have excessive amount of retracting, so just lower them enough to make it so it retracts.

Share this post


Link to post
Share on other sites

Yes right, I was able to figure it out checking at the layers view in Cura. By playing with parameters I was able to see the retraction (blue lines going up) on the concerned layers. Now I'll have to try it out but it will take time as I have to redo the 3D model as I have a problem of scale with the original/real one. I'll keep you inform.

Thanks again...

Share this post


Link to post
Share on other sites

Good evening,

I am done with modeling my part. I import my model on Cura then I switch on layer view. I focus on the layers concerning the topics (the rivets) then I need to have the settings as you can see on the picture to visualize a proper "Z hop". Would that setting work? does it influence the quality of the print or just the nozzle trajectory?

5a331482dbcfd_Capturedcran2015-11-3017_57_47.thumb.png.a162d884c37bc7c1be92fccdd6557c5a.png

Share this post


Link to post
Share on other sites

I advise against Z hop. It can greatly reduce the quality. It's most useful for delta printers, not X/Y printers.

I would print it as shown but I would also try printing the part up on the long edge (try both!). That way the rivets are a simple bump out and no retraction needed. I would also enable the brim feature if you print it on it's side to keep it from falling over during the print and possibly even add a few 45 degree supports to be removed later using cad software that meet the part half way up. But it should be fine without any supports.

Share this post


Link to post
Share on other sites

I would also grab the last layer printed from the gcode file and run it through something to count the G11 (retract) commands and also look at the extruder position (which is in cubic mm which is confusing) and try to figure out how many retractions there are per mm. Then knowing it retracts about 4mm or 4.5mm figure out how many times each spot of filament goes back and forth through the feeder. If it's more than 100 you will probably get grinding. But maybe not. I've done > 100 and been fine on some printers/filaments and on others it fails around 30 to 40 times having the same spot go through the feeder.

Share this post


Link to post
Share on other sites

No - but you may grind the filament into dust. For example I printed the eiffel tower which has hundreds of girders per layer - each tiny girder is a separate "island" on a layer. I actually had a half kilometer of retractions! On average each piece of filament went through the feeder 20 times and it was no problem.

Then on a different printer I was printing big ben and there was a few layers where there were 40 retractions per piece of filament and the filament ground down to half it's normal size and eventually failed. I had to reslice it with fewer retractions - it came out great.

Some printers/filaments can do 40 retractions per spot of filament without grinding it down too much. Other filaments get ground down until it can't feed anymore and the feeder stops feeding and the print fails (nothing extrudes).

There is absolutely no damage to the printer.

Share this post


Link to post
Share on other sites

Ok. I'll try to print it as I've programed it first (maybe tomorrow evening) if there is no risks for the printer, only risk of wasting a bit of material... Then I'll try later this week to print it standing as you suggested but for that I'll design the inner parts first. To be followed and thanks for sharing your experiences ;-)

Share this post


Link to post
Share on other sites

Trick to count G11 command : Edit the geode as text file, copy and paste in a spreadsheet then apply a filter that is equal to "G11" then count the remaining lines ... Maybe everyone already know but am happy to have found it ...

Anyway, the point is that from my gcode I can find 10548 "G11" ... may be too much...

Share this post


Link to post
Share on other sites

Sometimes if you do a find/replace all it tells you how many it replaced so you can change G11 to X11 and then undo. or use "find" dos command or "grep" unix command.

10548 is fine as long as it is a big enough print. 10548 X 4.5mm retraction (the default I think) is only 47 meters of retractions. I've had a half kilometer of retractions. But if you are only printing 1 meter of filament that's 47 retractions for each spot - marginal but might work. If you are printing 4 meters of filament that should be fine. More importantly just check ONE LAYER. the layer with the rivets.

Anyway you won't break anything - the worst thing that will happen is you will grind the filament at the feeder and have to remove the bowden at the feeder to get it out. Make sure you push down on the ring around the bowden while pulling up on the bowden. Perhaps use needle nose pliers for pushing down.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Our picks

    • Taking Advantage of DfAM
      This is a statement that’s often made about AM/3DP. I'll focus on the way DfAM can take advantage of some of the unique capabilities that AM and 3DP have to offer. I personally think that the use of AM/3DP for light-weighting is one of it’s most exciting possibilities and one that could play a key part in the sustainability of design and manufacturing in the future.
        • Like
      • 3 replies
×

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!