Buildlog.net Open Source Laser

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Re: Buildlog.net Open Source Laser

Postby Robert Williams » Sun Apr 25, 2010 3:26 am

[quote="bdring"][comment][/comment]Z motor is NEMA 23.

I could probably put both patterns on the motor bracket just for the fun of it. I get the pulleys next week. I did not order the belt yet, because I want to make sure everything fits right. I think I might give http://www.econobelt.com/ at try. The belts seem a lot cheaper than Stock Drive. The pulleys are about the same price.

Now that the laser is pretty productive, I might start selling part kits. I think I will start with an 6mm Acrylic part kit for the XY system, a 1/4" MDF part kit for the skins and an Acrylic one for the Z lift assembly. The kits would just be for the parts not available off the shelf. I might see about qty buys from the v bearing people to get the cost down on those expensive items. The cost would be less than you could get it at Ponoko or Pulolu.[/quote]

I'll buy your kits NOW!... I notched 4 floors before I got it right, 2 Z tables.
Robert
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Re: Buildlog.net Open Source Laser

Postby willyinaus » Sun Apr 25, 2010 5:48 am

Hey Ill buy a kit as well :D
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Z Table Bracket

Postby bdring » Sun Apr 25, 2010 4:24 pm

This is the table bracket I am going to try. This will bolt to the bottom of the table. It uses a T-Nut to ride on the threaded shaft. The T-Nut fits into a special pocket on the bracket. It has a little float to accommodate slight mis-aligned or non straight shafts. It is only held together with gravity. This allows very easy leveling of the table. If you need a corner to move up or down a little, you just lift the table and rotate the nut in 1/3 turn increments.
.
table_brkt1.JPG

table_brkt2.JPG

Note: This black Acrylic is really hard to take a picture of. It is like taking a picture of a mirror. I need to get a white light tent.
Bart
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Re: Buildlog.net Open Source Laser

Postby willyinaus » Sun Apr 25, 2010 9:46 pm

My white light tent is a pillowcase and two coat hangers bent to keep it up :D
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I hope it is worth it!

Postby bdring » Wed Apr 28, 2010 2:55 am

Remind again me why I tore down a working Z axis?

Here is the aftermath of my battle to get the old Z axis out. The floor had to be cut in half inside the enclosure to get it out. Good thing I have a great built in exhaust fan :D .
.
z_demo.jpg

Hopefully I will have all the parts by the weekend. I am sure I can keep myself busy cleaning up.
Bart
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...couple of time delays

Postby bdring » Sat May 01, 2010 12:08 am

I got sent half way across the country on unexpected business yesterday and my extrusions for the new z lift appear to be one their way to Ohio. I live in Illinois about 10 miles from where they ship the parts, but the tracking number shows them slowing going towards Ohio?

I think I will temporarily use the old extrusions so I can make sure everything fits as planned and swap in the part later.
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Re: Buildlog.net Open Source Laser

Postby lasersafe1 » Sat May 01, 2010 2:48 am

bdring wrote:
Comment From Buildlog Author
I might see about qty buys from the v bearing people to get the cost down on those expensive items.


I didn't want to be too critical, but I would suggest you might try something else for riding on the v-channel. I saw the video of your x axis driving fast and the noise seemed somthing horrific. Noise is one of the components of friction. My laser has the rubber wheels that ride in the groove and the movement is just a quiet "shoosh" from side to side. Perhaps you don't view it as a problem if your happy with your speeds and tolerances, but if there is a urethane or nylon wheel to try......

So the Universal laser uses rubber wheels, the Chinese lasers use rubber wheels... Might be a reason for it.
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Re: Buildlog.net Open Source Laser

Postby bdring » Sat May 01, 2010 3:00 am

That would be great if you could find some.

Actually, the noise is not an issue once the cover is down. The tiny motor board fan and steppers are actually louder. The wheel are strong and ridged as hell.

The real issue is cost. They cost about $10 each. They are probably the most overpriced item on the design. I just bought some nylon V wheels from Stock Drive, but the bearings are very loose. They might work under tension, but I am skeptical. I might try on a separate piece later.

I have looked around for rubber, plastic or nylon wheels and not found anything. I'll owe some real favors to anyone who can find a decent rubber wheel and riding surface combo. I even toyed with a press on nylon part to a standard bearing.
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Re: Buildlog.net Open Source Laser

Postby lasersafe1 » Sat May 01, 2010 1:16 pm

I bought a weight lifting machine from the thrift store and it had many bad pulleys. I bought some urethane razor scooter wheels that were $1 each at the dollar store and chucked them into a lathe* and turned it down to produce a negative groove for the lifting cables. It outperforms the original pulleys and is vitually silent. Now of course these wheels are too big for your application, but there might be something you can find that can be turned on a lathe.

*(note: it wasn't actually a lathe. I used my mill as the turner and had the cutter fixed in a vise)

If you're happy with metal, perhaps you can turn down the outer race of a standard skateboard bearing a 10 or 20 mils. Just enough of a groove to mate the v-rail. I would thing the outer race is at least 1/16" thick. Might be too much work.

Here is a link to a store that sells the ULS wheels. http://www.engraversnetwork.com/store/laser_bearings.html
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Re: Buildlog.net Open Source Laser

Postby bdring » Sat May 01, 2010 1:24 pm

That is a good link. I'll post it somewhere. I also searched for the track that the Chinese lasers run on, but found nothing. There has to be an extrusion house in China making them.

The races on most bearings are hardened, so it would probably need to be ground. You can get decent bearings with no play pretty cheaply. I though a press on nylon v-wheel "tire" for a bearing might work.
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