[DDM]

Hey everyone, I've been looking around for a sutible frame material and I thought I'd give the t slot style extruded aluminum a shot except it seems that the 8020.net website is down for the count and the Tslots.com online catalog isn't there. I didn't know if there were any other companies out there or what the deal is with 8020 and tslots. Thanks

Carl

[duluthboat]

Try here, they have it. http://www.reidtool.com/ There are others suppliers I can post them when I get to work.

Gary

[Al_The_Man]

Carl, Reid tool has all the 8020 and a lot more neat hardware, they also have everything in cad format for drawings.
www.reidtool.com also for extrusions see http://www.parker.com/ead/cm1.asp?cmid=809
Al

[Swede]

I like Bosch-Rexroth, online ordering, great variety. I can vouch for the quality of their extrusions. I like the 45x90 heavy, especially.

[NeoMoses]

I've got some for sale in the classifieds at the moment.

[DDM]

Ok, I've been looking and drooling on extruded aluminum here now that the 8020.net site is back up. Got a few questions though. First of all what does everyone think about the linear motion system they have for the 8020 system? I know it seems kinda different, no where close to the accuracy and percision of THK bearings and rails but it you were to fabricate you're own plastic runners and get their stick extruded stuff they use for bearings you'd be looking at at maybe 5 bucks per bearing and you've already got your rails if you made your entire system out of the 8020. I work in a machine shop and this wouldn't be any problem for me to do. The next 64,000 dollar question I have is what size to use. I see that Balsaman made his second router out of this stuff (Love your work man). I read through the entire post again, all 18 pages, and I couldn't find what size he used, my guess is 2x2. I'd like to build a servo powered moving gantry similar to Balsaman's with a work area of 24" by 36". It seems like a nice size but I was somewhat concerned about the deflection on the center of the y axis. Any suggestions you guys could give would be much appreciated.

Carl

[samualt]

I'm a newb so keep that in mind. I found 8020's Material Properties Calculator which lets you calculate deflection given length, weight, and other data. Its free and works good. I figured for my machine I needed the 1.5"x3" (1530 I think) and use it on it's side so that it is 3" tall (rather than laying flat).
Because my gantry is so long (54") I decided to put two of my motors ontop of the block bearings for the X-axis. That way I minimize the Z-Axis weight. I still may have to go to the 3"x3" extrusion for the gantry.
A 2"x2" extrusion seems small . A 2x2 that is 36" long will hold 28 lbs, at any one point, without deflecting. More weight will make it bend. A 1.5"x3" that is 36" long will hold 95 lbs without deflecting. That seems more reasonable to me.

The only advice I can give about THK rails is that it shouldn't be too expensive with the small sizes your talking about. I would think $200 would do it if you held out and checked ebay often. Price is relative though, there are people here who have built their whole machine for less than $200.

[arvidb]

Originally posted by samualt
*snip* A 2x2 that is 36" long will hold 28 lbs, at any one point, without deflecting. More weight will make it bend. A 1.5"x3" that is 36" long will hold 95 lbs without deflecting. *snip*

This can't be right. It deflects (a tiny tiny amount) even under its own weight! The question is not *if* it deflects, but how much it deflects holding a certain weight at a certain point.

I'm not sure about the terminology here, but to me, bending (as opposed to deflecting) is a plastic, permanent deformation.

Arvid

[High Seas]

DDM -
my System2 is made of 80/20 1530 (1.5x3.0 in). The (theoretical) working area is 40 inches x 28 inches, with 10 inches z. I say theoretical as my thk rails are still not (yet) long enough to max out that space except for the z. BUT - I have not noted any deflection worth worring about. Maybe I need to make some more bits and pieces - but busy on other "chores" now too.
:cheers: Jim