One-Week Build

General discussion of laser machines

Re: One-Week Build

Postby LeonS » Wed Mar 30, 2011 1:42 pm

Thanks for the measurement and analysis Tim. Looks like I might have some problems with my left rail. I'll know better in a week or so.

I would definitely upgrade to the integrated extrusions, too. I suspect that the sheet metal parts for the X rail ends would need to be replaced as part of the upgrade. So far, I see gluing the rails as being the least deterministic and most reliant on craft. It would be good to replace the glued rails with a unified engineered product that even I could succeed with.

Cheers and thanks again,
Leon
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Re: One-Week Build

Postby bdring » Wed Mar 30, 2011 2:26 pm

I will measure my system when I get home. I usually slide the carriages by hand as a test, so I don't expect much of a change.

I had experience with this situation on my very first router build. In that case my center was wider. It was like the carriage was climbing a hill then running down. When loose, it would actually free run from center to end end. I have been sensitive to that situation ever since and watch out for it.

You want a lot of speed out of the X, but the Y is not as important. I find that the Y is capable of a lot, but you will start to shake the machine at some point. I also find that you want to dial down the acceleration on the Y axis from what it appears to be able to do because all that mass can cause shaking of the machine and some of the looser parts like the cables and cable carriers might try to overshoot and work against a clean stop. Mach3 and and FSE are supposedly working on S curve acceleration that reduce jerk forces.

As far as the unified extrusion concept goes, it is 100% compatible with everything. I made changes to the original concept for this. See my latest post on it.
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New V-Rail

Postby twehr » Wed Mar 30, 2011 4:09 pm

New v-rail material arrived about an hour and a half ago. I cut it, cleaned it, marked placement, and practiced 15-20 times. Wanted to make sure I had a method that would allow me to ensure good mating for the full length.

I glued it up, just as I had practiced. After it sat for a few minutes, I did some quick, non-stressing measurements, just to see where I think I will be when done. See the table below that shows the old measurements and the new ones. If those numbers hold up, I think I will be really happy.

V-Rail Measurements2.png


If anyone cares to see it, I could make a video of how I glued it up. I am sure having a demo would have saved me a lot of time (and money).
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Re: One-Week Build

Postby LeonS » Wed Mar 30, 2011 4:12 pm

@tim
Well done! I think a video would be great if not too much trouble. Others can benefit.

@ Bart

Thanks for sharing Bart. Your experience makes a lot of sense. Gives me hope that my initial setup will work good enough. Put me done for the upgrade when it becomes available.

This design and the kits are awesome. Huge amounts of work by Bart. It is so appreciated.

Cheers,
Leon
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Re: One-Week Build

Postby cpdude » Wed Mar 30, 2011 4:28 pm

@Tim - Yes to the video. I think it would be very helpful.

@ Bart - I think you had mentioned using epoxy to glue the v rails before. I'm wonder if you recomend sticking with the Loctite Super Bonder Gel 409 or instead recomend using something like Hysol epoxy on my extend X and Y axes?

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Re: One-Week Build

Postby bdring » Wed Mar 30, 2011 4:39 pm

I had success with the epoxy (JB Weld) on my "buildlog bot" 3D printer, but it required many clamps and I was worried about an unknown layer thickness. It took all my clamps per rail so it took about 2-3 days to do all the rails. Since the setup time is so long, I was able to massage the rails back and forth many times to attempt to get an even layer, but I never knew for sure.

I thought the super glue would be a more deterministic solution... apparently not :?
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Re: One-Week Build

Postby cpdude » Wed Mar 30, 2011 4:51 pm

This doesn't sound like the end of the world...I'm interested in hearing more about the custom extrusions. I would be nice to have a bolt in replacement on the 2.x laser. ;)

Brian
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VRail Glue-Up Method

Postby twehr » Wed Mar 30, 2011 9:14 pm

After doing the x v-rail a second time, I am convinced that the super glue method IS a great solution (until we get extruded vrails, that is :mrgreen: ). The issue for me was technique. I'll do another measurement tomorrow but I have gone back and measured once again, finding that it may be even closer that I thought earlier today.

I promised a video on how to do the glue-up in an easy and hopefully foolproof way. Here it is. It ran a tiny bit longer than I could upload to YouTube in a single piece, so I broke it up into two. Did not have a lot of time to play with the editing, so there is about a 2-minute overlap from the end of the first to the beginning of the second. The repeated part is probably work seeing again anyway.

Part 1


Part 2


If anybody know a better way, let us all know.

Tomorrow, I will swap out the old/new x axis and test - then it is back to serious progress (I hope).
Last edited by twehr on Thu Apr 21, 2011 5:43 pm, edited 2 times in total.
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Re: Glue Method

Postby bdring » Wed Mar 30, 2011 11:10 pm

I measured my rails and mine tend to be a little fatter in the middle. The worst was my gantry which was 0.003" higher in the center.

I think I went through exactly the same steps as Tim except I put the glue on the rail and not the extrusion. My theory was that I would put the rail on with a wiping action and move glue towards the front and hopefully onto the other edge of the v rail.

I did get glue on my fingers and it is annoying and distracting. I got better by my sixth rail, but always got a little on my fingers and then the rails. The first rail was bad enough that it took about ten minutes of acetone and Scotchbrite to get the finger prints off the v rail.

Tim's method might be better for several reasons. The first is the glue on fingerprints issue. The second is that maybe glue on the other edge is not a good thing. Metal to metal might be the best you can get in terms of fit and there may be better tactile feedback.
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Re: One-Week Build

Postby LeonS » Thu Mar 31, 2011 12:24 am

@Tim

Great videos. These will be a big help to those following along. The main points I got were scoring the registration marks, practicing, and applying the glue to the 2040 support rather than the rail. I think the rail that has the most variance of the ones I did, was the first one I tried. I had all the problems of flipping the rail, glue on fingers, etc. that you alluded to. After that I got the hang of it. Your tutorial provides a very methodical approach which should help make mounting all the rails successful

I just mounted my lens carriage onto the long axis and it seems to move smoothly and evenly over the entire length of the rails. Whew! As Bart pointed out, that is the one that is most critical for high speed scanning.

I have been having trouble with one of the delrin rings slipping off of its bearing. Should I apply a tiny bit of super glue?

- Leon
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