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Madclicker
01-06-2007, 09:35 PM
My big 1/3 sheet router is so successful that I wanted to continue some of the best of that design and combine it with improvements I have discovered since I started that project.

In the near future I will build a full sheet machine(maybe call it MaxiMe), but I don't have the room for it right now.....so, I'm designing and building a smaller machine. I owe everyone on the zone that posted any unique ideas a debt, but I think Spalm (Steve) had the biggest influence on the direction I took with this machine. He and Benny were the first to use V bearings that I know of. Also, Steve is the only one I know of that attempted to make an improved DIY drive that wasn't just based on canned data sheet schematics. Blazing new ground is commendable.

I expect this little machine to be very fast and accurate. At first I will test it with my Gecko drive cabinet, but in the end the drives will be my own design.

I spent a couple hours modeling the base. I can see now why there are so many newbees with drawings and no results! It's kinda fun to draw this stuff, but work sucks!

spalm
01-08-2007, 09:24 AM
The trouble with blazing is the increased probability of getting burned.;)

Not sure if you are looking for comments on this design, but I have a few:

I like the open frame you have drawn so that the gantry can have a support across the bottom. It will make the gantry much more resistant to racking. I wish I had done this. However, it looks too feeble and might have the tendency to parallelogram when the machine gets a rocking. Maybe add some internal triangle supports to the ends.

It also looks like the bed does not have enough support to keep it flat. Maybe add a thin torsion box underneath it for support.

Also, why the bolts holding the wood together? Use dowels/biscuits and glue. Furthermore I have some concern with the rail bolts pulling out or coming loose. Maybe some kind of captured nut, threaded insert or even threaded rod running all the way through to the other side. You are probably going to have to adjust these rails for parallelism and possibly shim them for width adjustment.

I am still a big proponent of dual screws. Want to work out something new? Nobody that I can recall has gone with a single screw and cables/pulleys to keep the gantry riding square. This would be a lot cheaper than a second screw. Maybe just consider it so it could be added later.

Steve

Madclicker
01-08-2007, 11:40 AM
Thanks for the input.



I like the open frame you have drawn so that the gantry can have a support across the bottom. It will make the gantry much more resistant to racking. I wish I had done this. However, it looks too feeble and might have the tendency to parallelogram when the machine gets a rocking. Maybe add some internal triangle supports to the ends.

I hadn't planned on attaching the gantry to the bottom. I intended this to just complete the "box" of the bed and allow the machine to sit on saw horses. Did you have a big problem with racking using the v-bearings?

Or, are you talking about tying the gantry together at the bottom? Now, I recall that you didn't on your last.



It also looks like the bed does not have enough support to keep it flat. Maybe add a thin torsion box underneath it for support.

I thought long about whether to make the bed a torsion box or not. I have a 4' router table made much the same way and attached to my table saw. The only other support is a jack stand at the end. In 4 years it has sagged 1/16". My reasoning for this design being good enough to not sag appreciably is that there are the 2 angle rails solidly bolted the full length. Also, the 5 t-tracks extrusions will be screwed and epoxied. Finally, the top and bottom will get phenolic laminate. This creates a psuedo tosion box. I think you laminated the uprights on one of your builds and noticed the improvement in stiffness.




Also, why the bolts holding the wood together? Use dowels/biscuits and glue. Furthermore I have some concern with the rail bolts pulling out or coming loose. Maybe some kind of captured nut, threaded insert or even threaded rod running all the way through to the other side. You are probably going to have to adjust these rails for parallelism and possibly shim them for width adjustment.

The bolted design is for easy breakdown/assembly. Every place I have bolts there will be hardwood bisquited into the MDF with t-nuts for the threads. The bolts also allow the adjustments you mentioned.



I am still a big proponent of dual screws. Want to work out something new? Nobody that I can recall has gone with a single screw and cables/pulleys to keep the gantry riding square. This would be a lot cheaper than a second screw. Maybe just consider it so it could be added later.


I kept the cable/pulley option open on my first machine. Never had a problem with racking that couldn't be solved by "aping" the sides together.

I've decided to decrease the overall height of the bed to 7". This will give just enough clearance for a 3" lower gantry torsion box.

Madclicker
01-21-2007, 12:09 AM
Well, bought the motors for this. PacSci 34's and I can't find the data sheet for them. Oh well, time will tell if I did good. I think they will be 600+ oz/in based on the current/voltage specs on the label. Need to change my drawing to the pretty red colored motor...but, I did change the design height to 7". Hopefully I can squeeze everything I need to in the 4" hole. Pic 1

I have started cutting stuff for the base, but never enough hours in the day. After I get the top glued up I'll cut the t-track grooves on the original machine.

The motors I'm gonna use are almost 6A, so I definitely need more than hobby drives for this project also. This time around I'll design my own. I have some goals for this design:

1. 10A bipolar (probably less)
2. 70V (definite)
3. PIC based controller
4. Feedback compensated for resonance issues (very important)

This one will be more fun than the last because of the educational part. The last was just work to get a machine working.

Madclicker
01-25-2007, 12:32 AM
Got my motors today. Nice looking. Still can't find the data sheet.

Rance
01-26-2007, 07:30 AM
...Never had a problem with racking that couldn't be solved by "aping" the sides together...

OK Steve, I'll bite on this one. What is 'aping'. I'm a woodworker, should I know this already? :) Thanks.

Madclicker
01-26-2007, 11:39 AM
OK Steve, I'll bite on this one. What is 'aping'. I'm a woodworker, should I know this already? :) Thanks.

LOL.

aping: To pull on wrenches like an ape.

I think I picked this term up when I read about how some people ruined the collets on routers by "aping" on the wrenches.

I don't think I'll be able to use that technique with this machine, though. The v bearings ride differently than the skate bearings on pipe.

acondit
01-26-2007, 12:13 PM
Got my motors today. Nice looking. Still can't find the data sheet.

Steve,

I have a PacSci Stepper selection pdf (1.7mb) that lists the specs for E series (Sigmax Hybrid) steppers. If you post the model number, I will post the specs for that model. If you pm me with your e-mail address, I will send you a copy of the pdf, since it is to large to attach here.

Alan

Madclicker
01-26-2007, 03:07 PM
Steve,

I have a PacSci Stepper selection pdf (1.7mb) that lists the specs for E series (Sigmax Hybrid) steppers. If you post the model number, I will post the specs for that model. If you pm me with your e-mail address, I will send you a copy of the pdf, since it is to large to attach here.

Alan

Thanks, any help is appreciated.

Model: 802D3437-28774

I got a pretty good deal on these @ 3 delivered for $50. The guy has a bunch more. When I confirm they will work others may be interested.

Will PM my email. Thanks.

Madclicker
01-26-2007, 10:20 PM
Thanks for the data sheet Alan.

Looks like my original guess was right. These motors are somewhere between 627 and 679 oz/in.

I think these were a killer deal at less than $17 EA DELIVERED!

jmytyk
01-26-2007, 10:37 PM
um yes, please send the info for where to get 'em... thanks.

Madclicker
01-28-2007, 08:53 PM
um yes, please send the info for where to get 'em... thanks.

I got them from an individual. I'm trying to work out a deal for a quantity now.

Madclicker
01-28-2007, 09:01 PM
I cut and glued up the MDF blanks for the base. Not much to look at yet, but this is going to be a pretty easy and straight forward build. The top and ends are in the foreground. If you look in the background you can see the bottom leaning against 2 MAC roll-arounds. I'll finish and add the bottom toward the last so I have more working room underneath.

Madclicker
01-29-2007, 09:31 PM
I modeled the options for my Y axis rails. At least these are the one's I'm considering at this point. A few variations of V and flat bearings with common flat and angle iron.

If I go with V and flat bar, I'll use cold roll. I'm leaning toward this. I can get eccentric bushings for the V bearings. If I use flat bearings, I'll have to invent the adjustment mechanicals. My first inclination is to use just 1 V bearing on the bottom.....for cheapness sake. If I have problems holding the gantry down I can easily add another to each side.

joecnc2006
01-30-2007, 05:59 PM
1st off excuse the drawing, i just cut and paste yours since im at work right now, but i was thinking it might be better to have two vertical V-Bearings and two Horizontal V-bearings (these two on inside of machine) to avoid lateral pusing on the vertical v-bearings.

Joe

Madclicker
01-30-2007, 10:31 PM
1st off excuse the drawing, i just cut and paste yours since im at work right now, but i was thinking it might be better to have two vertical V-Bearings and two Horizontal V-bearings (these two on inside of machine) to avoid lateral pusing on the vertical v-bearings.

Joe

Well, that would work. It would also complicate mounting and adjusting the bearings. I can see using square tube for a mount, but not sure about easy adjustment. Also, I don't think lateral forces are a problem with these bearings. They've been used like this for years in shopbots.

Some more pics of what I'm leaning toward. Easy flat plate mount of the bearings and only 1 eccentric bushing to adjust the vertcal slop.

Madclicker
02-03-2007, 12:05 AM
More modeling. Bought quite a bit of stuff lately and some tangible results will show up here soon. Too few hours in the day. The pic is what I expect to have built shortly.

Greolt
02-03-2007, 01:35 AM
Easy flat plate mount of the bearings and only 1 eccentric bushing to adjust the vertcal slop.
I think you should put two on the bottom also. More rigid gantry.

Madclicker
02-03-2007, 11:40 PM
I think you should put two on the bottom also. More rigid gantry.

Like I said, I may have to. I'm trying 1 first because it seems all the rack and gear designs have only 1 point of contact on the lower side and work perfectly well. It's just the gear riding on the rack in every design I've seen. If it doesn't work, I'll add a couple wheels. If it does I save $40.

More models to confirm clearances. Also added Y rails and Y motor.

MarkMansfield
02-04-2007, 06:23 PM
Could I get a copy of the spec sheets for those stepper motors? Are more of them available?

Greolt
02-04-2007, 06:56 PM
Like I said, I may have to. I'm trying 1 first because it seems all the rack and gear designs have only 1 point of contact on the lower side and work perfectly well. It's just the gear riding on the rack in every design I've seen. If it doesn't work, I'll add a couple wheels. If it does I save $40.

In the machines that I think you are referring to the rollers are basicaly at the gantry height and would almost run without a bottom roller (or gear)

With your gantry design the screw providing the motion is below the line of the rollers and the weight of the Y and Z axis is well above that line.

When the axis changes direction etc the forces on the rollers are much more. Think triangles. :)

Hope that makes sense.

MarkMansfield
02-04-2007, 07:29 PM
Steve,

I have a PacSci Stepper selection pdf (1.7mb) that lists the specs for E series (Sigmax Hybrid) steppers. If you post the model number, I will post the specs for that model. If you pm me with your e-mail address, I will send you a copy of the pdf, since it is to large to attach here.

Alan

This is what I was looking for, the spec sheet for these stepper motors. You think I might could get a copy of that sent to my email link?mwmansfield@qwest.net

Madclicker
02-04-2007, 10:24 PM
This is what I was looking for, the spec sheet for these stepper motors. You think I might could get a copy of that sent to my email link?mwmansfield@qwest.net

I sent it. The model number on the motor does not match a standard PacSci number. I'm guessing that this is an in-house number. Based on the current stated on the label and the physical sive compared to standard part specs I put these at 600-700 oz/in and parallel connected.

Still talking to the guy to try to get more.

Madclicker
02-04-2007, 11:04 PM
In the machines that I think you are referring to the rollers are basicaly at the gantry height and would almost run without a bottom roller (or gear)

With your gantry design the screw providing the motion is below the line of the rollers and the weight of the Y and Z axis is well above that line.

When the axis changes direction etc the forces on the rollers are much more. Think triangles. :)

Hope that makes sense.

You are right. I'm hard headed. (chair) Pushing and pulling from the bottom and dragging a bit on the top will introduce forces I didn't even consider. Now that I think about it, this design (1 lower bearing) would be no better than a 4 bearing truck of half the length.

Madclicker
02-05-2007, 12:49 AM
OK, new changes based on constructive criticism. 2 lower v-bearings on the bottom. Also, I prettied up the model of the bed to include a real t-track model. This cad stuff is much more fun than work.

Madclicker
02-07-2007, 02:22 AM
Modelled the screws and couples for x and y.

Madclicker
02-08-2007, 02:16 AM
Started modelling the Z. Mounted the plate and then moved the screw/motor assy back. Obvious that I'll have to redesign the gantry upright dimensions, but that's expected. They are torsion boxes, so final design wasn't going to happen until the size was final anyway.

Madclicker
03-18-2007, 02:25 AM
I started on my drive design. Big learning curve with Eagle, but it's coming together.

I pretty much have the power stage figured out. Pic 1.

Not much really, the bells and whistles will be in the control board.

Madclicker
03-30-2007, 12:17 AM
Pretty close to being happy with the design drawing.