Buildlog.net Open Source Laser

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Re: Buildlog.net Open Source Laser

Postby bdring » Fri Feb 19, 2010 1:39 pm

I have been trying to make it simpler to fabricate all the parts. I want a decent laser cutter to be able to make complete set of parts for another laser. Obviously there will be a few places to drill and tap, but the bulk of the work should be done by the laser.

The bearings are 3/16" thick and the acrylic is 6mm 0r 0.25" thick. There were a few places where bearings mounted in counter bored holes. This is a tough hole to make without a CNC router.

I think I have a workable solution. A through hole is sized for a tight fit on the bearing. The bearing is pressed into the hole then a oring is is used to hold it in place with some #4-40 hardware and washers. The oring is hard at 70 durometer and cheap at $3 per 100 at McMaster Carr.

I should be cutting some parts pretty soon. I am still waiting for a part for my router. A lot more of the parts are now made out of Acrylic and they all easily fit on a medium sized (P2) sheet from Ponoko
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oring_clamp.jpg
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Re: Buildlog.net Open Source Laser

Postby 8bithack » Sat Feb 20, 2010 2:44 am

I would like to try and get some parts cut from Pololu before my rails get here on the 5th of March. Could you email me the laser cutting file for all the laser cut parts? I've been trying to put something together in Inkscape but it is taking a lot of time. Thanks.
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Re: Buildlog.net Open Source Laser

Postby bdring » Sat Feb 20, 2010 1:14 pm

I posted the "All Acrylic Parts" drawing on my drawings page. These are the parts laid out as I am going to cut them next week. The parts have been redesigned since the first version to power the Y axis from both ends and to consolidate most of the parts to something a laser can cut. I have a lot more work to do on the individual drawings. I have a very busy week coming up and will try to get what I can posted. I want to add the Z lift parts to this drawing eventually too.

I won't be able to make a drawing specifically for Ponoko or Pulolu right now. I had a lot of trouble making one for Ponoko before, because I don't have the exact versions of the software that they require and Inkscape does not have a way to go from CAD (at least not when I checked). I plan on getting my Corel upgraded, but that will not happen this week. I had won some free cutting from Ponoko, so they actually fixed the problems for me "this time only".
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Drawing here
cut_parts.JPG
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Acrylic Parts Cut

Postby bdring » Tue Feb 23, 2010 4:24 am

I was able to cut the parts. This is most of them. I will start to install them tomorrow night. The little belt clamps work great. I might change to three screws instead of four for mounting the bearings. I reduced the hole size for the bearing by about .003 to get a press fit.
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cut_parts.jpg
Cut Acrylic Parts
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Re: Buildlog.net Open Source Laser

Postby lasersafe1 » Tue Feb 23, 2010 3:51 pm

Wow! You are remarkebly close the the "24 hour laser engraver project". I would bet if all parts could be ordered cut to size then it could actually be done in a day.
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Rant: How thick is 1/4" Acrylic?

Postby bdring » Wed Feb 24, 2010 1:55 pm

How thick is 1/4" Acrylic? How wide is a 2x4?

I use a lot of Polycarbonate (Lexan) and some Acrylic (Plexiglas) at work. I have long known that 1/4" is really 0.236 (6mm) thick. The material I ordered from rlplastics.com was advertised as 0.250" thick. Usually when someone specifies a dimension to that precision, you should expect to get it. I really did not care if I got 0.236", but would prefer the 0.250".

Everyone knows U.S. 2x4 lumber is really like 1.5" x 3.5", but if someone were advertising 2.000" x 4.000" lumber, you should wonder what you are getting.

Anyway, what I actually received is 0.205"? Their web site actually has an F.A.Q. saying 1/4" is 0.236 and beware of companies that might supply material as thin as 0.220. So whats with this 0.205" stuff.....awaiting answers.

Now, all my stuff is cut thinner than expected. Most of the parts will be fine, but some have tapped holes in the edge that I am worried about. The two X Axis really should have the added stiffness too.
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205.jpg
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Re: Buildlog.net Open Source Laser

Postby lasersafe1 » Wed Feb 24, 2010 6:30 pm

Perhaps they were quoting British inches? I would demand a redo or refund.
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New Y Axis Drawings

Postby bdring » Fri Feb 26, 2010 4:04 am

I posted most of the drawings for the Y axis modification on the drawings page.

There a a few more to go and the assemblies drawing are not a 100%, but I know some people are actively building, so I want to get what I could online.
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Re: Buildlog.net Open Source Laser

Postby Robert Williams » Mon Mar 01, 2010 2:18 am

Thanks... I'm one of active builders. Need info on NEMA 17 stepper motor so I can order.
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Re: Buildlog.net Open Source Laser

Postby bdring » Mon Mar 01, 2010 2:29 pm

Comment From Buildlog Author

I bought mine here.

http://www.kelinginc.net/
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