[montreal333]

After accumulating a bunch of parts, a new build was started today. About a year or two ago I started a 48" x 48" build that stalled when I just couldn't decide on ballscrews or 1/2-10 5 start acme. It got put on the back burner but will be resurrected after this machine is finished.

This ones a bit smaller because I'm just using what I have on hand.

Z axis is a PBC Linear 'slide' @ about 11"
Y axis is a Thompson @ about 39"
X axis is unbranded @ about 19"
Extruded 8020 type frame and other misc odds and ends. Again, this is all being done with what I have on hand, I don't want to spend anything on it other then for a router of some kind. Probably a colt router. Cheap.

I'm using PBC redi rails and carriages on the x axis. As you can see in the picture, I have about 40 of them. Perfect for this machine, and easily adjustable. I have bigger carriages and rails but with only 19" on the X, the 4" redi carriages fit perfect. The 48" x 48" that's waiting to be finished is using 5" redi rails and 10" x 10" carriages. Very solid and will use duel screws, though I'd rather use R&P.

The gantry sides on this build will be 1/4" aluminum channeling. If there's any flex I'll bolt some steel angle to it. I have 1/2 inch aluminum plating I'd rather use but I have no way to cut it. I have an amazingly pathetic limited amount of tools to work with so I'm having to rely mostly on ingenuity to get the job done. It's like having puzzle pieces from a bunch of different puzzles and I'm just fitting pieces together until they make their own picture.

I originally purchased 6, 5 phase Vexta (?) motors and drivers off eBay. 3 for the big machine and I'll use the other three on this one. They're about 300oz and have gearboxes attached, though I don't know if the gear boxes are a good thing or not. May need bigger steppers anyhow, at least for the x axis, as this has some weight to it. X axis is 1/2", y and z are 1/4" so a bigger motor on X...??

I'm going to try and figure out how to get a frame built around the x axis tomorrow. It's self contained with very few places to actually bolt it to the frame without some modifying. Have to see what I can come up with. Z axis to the Y axis is pretty much done other then figuring out motor mounts. Once the x axis and frame is figured out I'll work on the gantry sides and how to tie them to the Y axis. Once that's done I'll have to work on electronics.

Throwing a bunch of pics up. Please feel free to comment, criticize, laugh, or encourage. AND, if you by chance have anything I can use for the bigger machine (ballscrews, acme stuff, R&P stuff, steppers and drivers...) that you would like to sell or trade, shoot me a message.

-Michael

[montreal333]

A few more pics.

The pic of the gear reducers are 10-1 reducers. The aluminum casings have oxidation on them and a bit of surface rust but they are still smooth as silk. I have no idea what I'm going to do with them but the prize was right.

[montreal333]

Attaching the gantry to the Y axis is going to be a little tricky. Not much progress today other then laying out the frame.

[awerby]

What are you using to drive those 5-phase motors? Gear motors in general aren't great for CNC machines, since they introduce backlash errors and trade speed for torque. Particularly if you're cutting wood, you need all the speed you can get - but not all the backlash.

[montreal333]

What are you using to drive those 5-phase motors? Gear motors in general aren't great for CNC machines, since they introduce backlash errors and trade speed for torque. Particularly if you're cutting wood, you need all the speed you can get - but not all the backlash.

Here are pics of the driver and the stepper. I bought 6 of them awhile back, all came together.

When I got them I couldn't find any info online so I sent OMC an email asking for specs. I was told they are an older motor no longer being made. I don't remember why, maybe it was in the email, but I want to say I remember them being just short of 300oz motors.

I didn't think about backlash in the gearing but, not that this is scientific, I can't feel any play in the shaft at all. That may change once they're powers up.

I want this machine to cut aluminum primarily, wood maybe down the road. I have another machine I was building and would like this smaller machine to make parts for the larger one. Motor mounts and such. I'm good with a decent to slow speed as long as it has an acceptable cut.

The larger 48" x 48" machine will be used for wood. If I can get it without breaking the bank, or the wife breaking me, I want to go with dual R&P on the larger machine.

I'm also trying to talk myself into buying a stepper/driver package with larger steppers. I've hooked mine up twice to a computer to test them and it was an all day evert both times to get them running correctly. Maybe I'm missing something but buying a package seems like a simple solution for both current possible underpowered steppers and ease of setup. I'll give these ones a go, since I already have them, but if they wash out, news ones are only a click away.

[montreal333]

Odds and ends. I have buckets of em' so, at the end of the day, here's where I stand.

I found corner brackets and some plates so I used them on some 3" 8020 for the 'legs' that I'll bolt a piece of mdf sacrifice board to. Have to go with a 1" board unless I can find a way to support the middle of the board without getting in the way of the x axis gantry drive bar (don't know what that's actually called. The bar that ties both sides of the gantry together and is attached to the x axis ballscrew nut.)

The frame is pretty solid but I'm not happy with the corner brackets. I'll see about maybe making some at work tomorrow or the next day.

In the picture are just some 8" scrap rails I have on the x axis. I have a 47" piece that I'm going to cut in half. The hardened steel v rail was too much for my sawzall, so I'll cut that in half tomorrow at work as well.

I'm still at odds with what to use for the gantry uprights. I can work with the 1/4" channel, but I'm worried about flexing. The 1/2" plating would be more tricky but solid. The Thompson Y axis will have to have holes drilled in the ends, corresponding holes drilled in the 1/2" plating and then bolted. I'm not going to try and tap the holes but rather just bolt it. I don't know if I can get away with eyeballing the holes or not. Rudimentary tools will help but it'll pretty much be a 'cross my fingers' and get it as close as I can kind of job. Lots of work wasted if I don't get the holes right the first time. I have some 3" square 8020 I could cut and use, but I've been saving those pieces for the frame on the bigger machine. Maybe if I root around I can find something to brace the 1/4" channeling and use it after all.

Anyhow, the pics are of the fame, x axis, the legs for the mdf bed, and what the x axis carriages will look like. The carriages will be about a 1/2" higher, and off the table, once they're bolted on. The frame will sit on a table pretty much as it is in the picture. I think I'd be able to bolt it all the way around to a table for added rigidity.

I've so far managed to not spend any money on this build but, taking into account what I originally paid for everything I've used, my best guess is that it's cost me less then $50 so far. Almost everything I have was purchased for scrap weight. I think it was .07 cents a pound for the steel and .70 a pound for the aluminum. The carriages I got at a yard sale two years ago, $20 for three milk crates full. I'll still need to purchase a spindle or a router, and possibly steppers and drivers.

I would like to get the gantry uprights figured out tomorrow and start figuring out how to bolt the Y axis up. If it's too hot, it's been in the upper 90's for the past week, then I may fire up Mach 3, hook the steppers up, and see if I can get them working again.
-Michael

Ps. Sorry, long winded cos' I'm pretty tired. Been a long, hot day today. I also forgot to rotate a couple of the pics

[montreal333]

Took the piece I needed to cut in half for the side rails to work today and, even with the chop saw, it took a bit to cut through. Here's some pics of the rails and carriages. Might try and bolt those on tonight.

[montreal333]

Drilled the side rails and bolted then in and, just for the heck if it, drilled and attached the carriages to some steel I had laying around for the gantry uprights. They're about 2" too short but I may use them anyhow. Pretty solid. That'll leave about 4" from the bottom of the z to the top of the bed. Originally planned on that being 6 or 7 inches.

I need to beef up the frame. I attached the carriages, with the steel gantry uprights, to the rails and they both leaned outward. I'll fix that tomorrow.

Here's a few pics.

[montreal333]

May be worth a quick look:

My son is part of a FRC robotics team who made it to worlds last year in St Louis and finished 17th. There were 7 kids on the team and it was their rookie year. Amazing young minds.

I found this while looking up parts for next years competition. Thought I'd share.

http://www.andymark.com/REVRobotics-s/534.htm

http://www.revrobotics.com/products/

Wish all extrusion took standards nuts instead of the overpriced ones you're forced to buy (or grinding down standard nuts to fit)

[montreal333]

May be worth a quick look:

My son is part of a FRC robotics team who made it to worlds last year in St Louis and finished 17th. There were 7 kids on the team and it was their rookie year. Amazing young minds.

I found this while looking up parts for next years competition. Thought I'd share.



http://www.andymark.com/REVRobotics-s/534.htm

http://www.revrobotics.com/products/

Wish all extrusion took standards nuts instead of the overpriced ones you're forced to buy (or grinding down standard nuts to fit)

Forgot to add pic

[montreal333]

Not a whole lot of progress in the last couple of days. I bolted the Y axis to the X axis, it came out pretty good, level and smooth on the bearings, no binding.

I took the X axis assembly apart to clean it, it was full of who knows what, and at some point I banged the threads for the locking nut on the ballscrew and now the nut won't screw back on. It was a 19" ball screw with bearing blocks. I took the nut off re 19" and put it in another one I had thats 23" long. Worked perfect. I also got that whole assembly locked down to the frame. I still need to tie that to the gantry with a piece of 2 1/2 inch aluminum I have. Once that's done, I need to go through and maybe put a little loctight on on writhin. Once that's done then the electronics can go on.

Getting closer by the day. Still need a router or spindle though.

[montreal333]

90% done. Need motor mounts and a few hardware odds and ends. Once that's done my son will start putting the electronics on it. Ended up being a very solid, very smooth, machine.

[montreal333]

Today I picked up 3 aluminum rails with integrated hardened steel V rails. They're 59" long, 9" wide and about an inch thick. No use for them yet but I'm sure I'll be able to think of something if I get more steppers to use with them. They need a good cleaning, and have a few dings in them, but the steel is in perfect shape and they're straight as an arrow.

[awerby]

Check out the Shopbot "buddy" system. They use extrusions like that, fitted with V-rails, to mount a moving table to, fixing a rack to the bottom and sliding it back and forth between fixed rollers. I've got one, and it works pretty well.

[Aaron Bruce]

Great jobs! Good luck to you!

[montreal333]

Great jobs! Good luck to you!

Aaron,

Thank you. So far luck has been my blueprint. Hopefully it continues to guid me faithfully.*

[montreal333]

Check out the Shopbot "buddy" system. They use extrusions like that, fitted with V-rails, to mount a moving table to, fixing a rack to the bottom and sliding it back and forth between fixed rollers. I've got one, and it works pretty well.

Awerby,

I thought about doing something like, though I didn't know that was how the shopbot buddy was set up. My only concerns I had while mulling it over was supporting the outside edges of the table (or keeping it narrow enough not to need support), and the space needed in front and behind for the table. I also thought about building a 'regular' gantry cnc machine that would be 59" long and maybe 10-12" wide. Be good for making guitar necks, intricate interior house trim, or those 'love you to the moon and back' signs you find at tourist traps.....one piece hockey sticks? Precision yard sticks? Really long back scratchers??*

What I really need, before I can do anything like start a third project, is I need to get some stepper motors and drivers!! I jumped the gun when I bought mine and now I'm worried there won't be enough motor to do the job properly. Because they have a gearbox attached, the shaft is off center. If I go ahead and make motor mounts for these and they don't work out, I'll have to make new mounts for better, non geared, motors with a centered shaft. If that makes sense. I received an email from orential motor company and was told these are 290oz motors. Theres pics of them in another post of mine from a year or so ago. They seem awfully small if you were to remove the gearbox. I paid $90 for the six motors (they're 5 phase), six drivers, and a power supply for 3 of them. I really need to learn about steppers before I buy any more.*

-Mikey

[montreal333]

Well, the only thing I've managed to do in the past week was finally getting around to putting these 90 degree brackets on. I made 4 of them and plan on making 4 narrower ones to replace the triangular brackets that can be seen in the corners. Hopefully they'll be strong enough to square everything up and keep everything from moving. I seem to still be struggling with the motor mounts, I need to order some couplers to get the spacing. I made a few but, for the price, I may as well get good ones. Oh well, maybe next week I can get more done. )

Btw, the pics seem to rotate sideways when I uploaded them. Sorry.

[montreal333]

I made some brackets for the inside corners of the base. I'll leave the small triangle brackets in there as well. The new brackets are 1/4" aluminum, and I still have to drill the holes in them for the bolts. That'll have to wait for another day.

[awerby]

What Shopbot does to support the edges of their moving table is provide a pair of outboard support rails that go to the floor and have rollers on top. It seems to work pretty well: http://www.shopbottools.com/ShopBotD...%2009%2022.pdf

I share your concerns about those gear-motors. I don't think they'll have enough speed to do a good job on wood (which wants to be cut pretty fast) and the gears will introduce unwanted backlash. I'd put them aside and make mounts for standard 2-phase steppers, probably using a rack-and-pinion system like the CNCRouterParts machines.