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Tool alignment - how?

Posted: Tue Sep 08, 2015 4:47 pm
by nirfriedman
So, I managed to get the kit, firmware etc to work. Now I want to align the tools properly. Test prints are pretty good, but there is a slight bump along a wall that switches from one extruder to the other.

Any suggestions on how to go about doing this? I am thinking of designing a part that will allow to figure out what is the right x/y offset from the current setting, but wonder if this has been done already.

Thanks!

Nir

Re: Tool alignment - how?

Posted: Tue Sep 08, 2015 6:01 pm
by jsc
Files and process are discussed in the wiki: http://makergear.wikidot.com/dual#toc12

Re: Tool alignment - how?

Posted: Tue Sep 08, 2015 7:22 pm
by nirfriedman
jsc wrote:Files and process are discussed in the wiki: http://makergear.wikidot.com/dual#toc12
Thanks. I am doing that, but this mean doing trial and error and at each doing a rather large print. I was wondering if more efficient process can work. For example printing an object like the one below where the space between the two pieces increases in jumps of .1mm
test-tools2.png
test-tools2.png (9.41 KiB) Viewed 4648 times
test-tools.png
test-tools.png (33.06 KiB) Viewed 4648 times

Re: Tool alignment - how?

Posted: Tue Sep 08, 2015 7:48 pm
by jsc
That's a good idea, but I would set up a print where you try to align end to end instead of edge to edge. The slicer settings can effect that, there are some "overlap" settings that control the amount of merging between coincident edges. If you align end to end, it should avoid that. I'm envisioning a single layer of lines that are slightly offset more and more, like a Vernier scale.

Re: Tool alignment - how?

Posted: Tue Sep 08, 2015 10:33 pm
by nirfriedman
jsc wrote:That's a good idea, but I would set up a print where you try to align end to end instead of edge to edge. The slicer settings can effect that, there are some "overlap" settings that control the amount of merging between coincident edges. If you align end to end, it should avoid that. I'm envisioning a single layer of lines that are slightly offset more and more, like a Vernier scale.
End to end? not sure if I get your meaning here.

Re: Tool alignment - how?

Posted: Tue Sep 08, 2015 11:24 pm
by jsc
Google "Vernier scale" for an image. Here's one: https://en.m.wikipedia.org/wiki/File:Cl ... _scale.jpg

Then make a two part model, one for each side of the scale, with the center pair lined up and the lines on one side offset by .1 millimeter more on either side as you go out. Which pair or lines that line up will tell you how much your x separation needs to be adjusted by.

Re: Tool alignment - how?

Posted: Wed Sep 09, 2015 2:09 am
by nirfriedman
jsc wrote:Google "Vernier scale" for an image. Here's one: https://en.m.wikipedia.org/wiki/File:Cl ... _scale.jpg

Then make a two part model, one for each side of the scale, with the center pair lined up and the lines on one side offset by .1 millimeter more on either side as you go out. Which pair or lines that line up will tell you how much your x separation needs to be adjusted by.
I know what Vernier scale is, I was trying to understand what you meant by "ends" touching and not "edges".

Re: Tool alignment - how?

Posted: Wed Sep 09, 2015 2:17 am
by nirfriedman
nirfriedman wrote:
jsc wrote:Google "Vernier scale" for an image. Here's one: https://en.m.wikipedia.org/wiki/File:Cl ... _scale.jpg

Then make a two part model, one for each side of the scale, with the center pair lined up and the lines on one side offset by .1 millimeter more on either side as you go out. Which pair or lines that line up will tell you how much your x separation needs to be adjusted by.
I know what Vernier scale is, I was trying to understand what you meant by "ends" touching and not "edges".
I think now I got your meaning.

I managed to create this file which Simplify3D is willing to slice - each shift is 0.05mm which I think is fine enough. Each line is one extrude operation, so it is as thin as it can get. I'll try it tomorrow and if it works will upload to thingniverse....
offset.png
offset.png (4.96 KiB) Viewed 4593 times
update: this is on thingverse - http://www.thingiverse.com/thing:1006549

When printing I get (not the very best quality print :-( ) but the right alignment is somewhere in the area marked by the red circle
P9101427.jpg
P9101427.jpg (170.04 KiB) Viewed 4575 times
I probably should make one for the range -0.5-0.5 as it is very hard to read the scale right now...

Re: Tool alignment - how?

Posted: Thu Jun 29, 2017 5:59 am
by DrRobot
Sorry for replying to an old post, but I just upgraded to dual extruder and I am on the same page:) You can print the file mentioned on http://makergear.wikidot.com/dual and send M218 T1 Xn on the fly and observe the alignment when printing. However, my question is how to save this offset on the printer? Everytime when I restart S3D, this offset will be reset to default: 31.1mm. Thanks!

Edit: After some research, I found out the command is M500 to save to the EEPROM (This didn't work for me). Other options are changing it in the firmware Configuration.h, or adding M218 T1 Xn in the starting script

Re: Tool alignment - how?

Posted: Thu Mar 29, 2018 9:54 pm
by b-morgan
Am I correct in assuming that to measure the offset in Y, I should just rotate both parts 90 degrees?