Jump to content
Ultimaker Community of 3D Printing Experts
Sign in to follow this  
eldrick

Need Random Periphery Start/End-points

Recommended Posts

I manufacture a part for sport fencing, which is basically a slightly-tapered hollow cylinder about the size and shape of a thumb.

Since there are no corners to "hide" the start/endpoints, any regularity in their placement is very obvious to the eye, and 14.03 does a lousy job of randomizing the starts. On this piece, most of the dots wind up organized into two columns spaced about 2mm apart or in short vertical segments 3-4mm long.

This is very annoying and looks even worse with the smooth surface texture that Cura provides other wise.

Could we possibly either get a Random checkbox, or really randomize the default start points so they are more-or-less evenly distributed around a rounded piece?

 

Share this post


Link to post
Share on other sites

If the walls are .4mm thick meaning it only makes *one* pass and never goes back to the same spot on the same wall a second time and if there are no holes in the walls of the piece and no non-printing moves and no retraction then you can probably use the "spiralize" feature which adjusts the Z position very gradually along each layer so that there is no Z seam - every move includes a tiny increase in Z.

However if your part isn't incredibly thin then you can't use spiralize and I'm not sure what you can do.

I guess I recommend tuning the Z axis - try doubling the Z acceleration. Each doubling of acceleration means the movement is 1.4X faster (square root of 2) which means the blobs are 1.4X smaller. Increasing Z jerk also speeds things up. But if you increase acceleration too much you will lose steps and your part will be the wrong height. That's why you need to experiment - make long 10 to 50mm moves up and down and verify that the Z comes right back to the same starting point. I recommend pronterface to play with acceleration and to do the movements:

printrun/pronterface/prontrface download:

http://koti.kapsi.fi/~kliment/printrun/

Another way to shrink the blobs is to print slower so that there is less pressure in the print head. Try printing at half speed and see if that makes a difference. I don't know if your reprap has marlin but if so you can do this on the fly with feed rate control. I have found that printing at 30mm/sec with .1mm layers makes the Z seem almost disappear completely due to the pressure in the nozzle being so much lower.

Another way to shrink blobs is to lower temperature so that the PLA flows more like toothpaste and less like honey. For example 190C might give you smaller blobs than at 220C (although this also raises the pressure which could paradoxically make the blobs bigger so lowering XY speed might be better).

 

 

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
Sign in to follow this  

  • Our picks

    • Introducing Ultimaker Cura 3.6 | Beta
      Ultimaker Cura 3.6 | Beta is available. It comes with new features, bug fixes, and UX improvements. We would really like to have your feedback on it to make our stable release as good as it can be. As always, you can download the beta for free from our website, for Windows, MacOS, and Linux.
        • Like
      • 95 replies
    • Print Core CC | Red for Ruby
      Q: For some users, abrasive materials may be a new subject matter. Can you explain what it is that makes a material abrasive when you are not sure which print core to use?
      A: Materials which are hard in a solid piece (like metals, ceramics and carbon fibers) will generally also wear down the nozzle. In general one should assume...
        • Like
      • 30 replies
    • "Back To The Future" using Generative Design & Investment Casting
      Designing for light-weight parts is becoming more important, and I’m a firm believer in the need to produce lighter weight, less over-engineered parts for the future. This is for sustainability reasons because we need to be using less raw materials and, in things like transportation, it impacts the energy usage of the product during it’s service life.
        • Like
      • 12 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!