[Falcon69]

okay, so, umm, I'm done designing the Z-Axis then? LOL

Now i just gotta come up with the cash to get the stuff cut out.

I need to find a good welder also. I wonder if I could just tack weld everything up and then send it to someone who knows what they are doing to weld it up. Everything fits together with slots, so it should go together pretty square.

So, anyone know of a reasonably priced shop that does water-jet cutting and welding in the Portland, OR/Vancouver, WA area?

All those holes I have milled into the gantry and Z-Axis may or may not be there. I put them there to keep the weight down, but I may not be able to afford the cut-out charge. I called one place. It looks like the general cost is per inch the machine has to move. If I don't put the holes in to lighten it up some, I just hope it won't be too heavy.

[louieatienza]

okay, so, umm, I'm done designing the Z-Axis then? LOL

Now i just gotta come up with the cash to get the stuff cut out.

I need to find a good welder also. I wonder if I could just tack weld everything up and then send it to someone who knows what they are doing to weld it up. Everything fits together with slots, so it should go together pretty square.

So, anyone know of a reasonably priced shop that does water-jet cutting and welding in the Portland, OR/Vancouver, WA area?

All those holes I have milled into the gantry and Z-Axis may or may not be there. I put them there to keep the weight down, but I may not be able to afford the cut-out charge. I called one place. It looks like the general cost is per inch the machine has to move. If I don't put the holes in to lighten it up some, I just hope it won't be too heavy.

With those large steppers, I don't think you need to worry too much about weight! Weight can be your friend!

[Falcon69]

haha, yes. I should probably bolt the machine to the concrete floor to keep it from walking out of the shop. Those fast movemets of stop and go will surely make a machine 'walk'. I would think anyway.

[Falcon69]

I've been playing around with a few name tags/logos for my machine. what ya think of this one?

[vtx1029]

Nice job on the z axis I really like it!:cheers:

[ger21]

When you get that all welded together, it's all going to warp.
The tolerances required for that Z axis design are very critical, so I'd think that you may need to have all the bearing surfaces machined after welding.

I'd personally go with 20mm for the X and Y, as you'll find that they are easier to work with than the 15's, which are very small and use small 4mm bolts for mounting.
The 15's should be fine for the Z axis, though.

[louieatienza]

When you get that all welded together, it's all going to warp.
The tolerances required for that Z axis design are very critical, so I'd think that you may need to have all the bearing surfaces machined after welding.

I'd personally go with 20mm for the X and Y, as you'll find that they are easier to work with than the 15's, which are very small and use small 4mm bolts for mounting.
The 15's should be fine for the Z axis, though.

Related to that, if your local firm's waterjet is not 5-axis, and has some sort of "kerf compensation" the waterjet leaves a tiny draft angle (maybe .001"-.004") because there is a slight amount of spray-back depending on the material thickness. So this is something to be aware of on butt joints and any "interlocking" joints...

The logo is cool but I think I've seen that before... LOL

Check also, it might be cheaper to have those holes CNC machined or lasered...

[Falcon69]

Gerry,
Yes, I am using 25mm on the Y-Axis and 20mm on the X-Axis.

Okay, I can plan on getting it machined. Shouldn't be that much cash to get it flattened. I should probably change the design just a little to add for the machining. How much, maybe .005 added to it? Like, say, if I have it drawn for 24mm (.945") spacing now between bearing and rail, I should make it .94" ? Or, seeing that the mounting surface is 3/8" thick, maybe just leave it the way it is, since there's plenty of material to take away?

Louie,
I checked on that. The machine leaves .001" kerf. I've allowed for that. If the tab is 1/4"x3/4", I've allowed myself 1/256" around it for the slot, that's .004" around the tabs for spacing for kerfs, etc.

Have you seen the Logo on another machine? I haven't seen it. I was just messing around with the splining tool on SolidWorks one day and just came up with the design.

The problem with CNCLaser, is it heat treats the material, hardening it, so I've been told. That will make it a little tougher to Tap the holes for threading. But you are right, for the thickness I am working with, it is cheaper. If my material had been like 4 inches thick, then Water-Jet would be cheaper. I'll check into it more. Does Laser leave a Kerf as well? The material is 1/4", 3/8" and 1/2" (1/2 inch for the router mounts) mild steel.


VTX,
Thanks!

I was also thinking about getting everything Powder Coated as well after it's been welded up and sanded. How much do you think I need to add to the bearing surfaces to allow for the thickness of the powder coating? I don't want the bearings to be too tight. I'd have to do this to the Z-Axis and the Y-Axis, as the X-axis just floats off the rails.

[louieatienza]

Gerry,
Yes, I am using 25mm on the Y-Axis and 20mm on the X-Axis.

Okay, I can plan on getting it machined. Shouldn't be that much cash to get it flattened. I should probably change the design just a little to add for the machining. How much, maybe .005 added to it? Like, say, if I have it drawn for 24mm (.945") spacing now between bearing and rail, I should make it .94" ? Or, seeing that the mounting surface is 3/8" thick, maybe just leave it the way it is, since there's plenty of material to take away?

Louie,
I checked on that. The machine leaves .001" kerf. I've allowed for that. If the tab is 1/4"x3/4", I've allowed myself 1/256" around it for the slot, that's .004" around the tabs for spacing for kerfs, etc.

Have you seen the Logo on another machine? I haven't seen it. I was just messing around with the splining tool on SolidWorks one day and just came up with the design.

The problem with CNCLaser, is it heat treats the material, hardening it, so I've been told. That will make it a little tougher to Tap the holes for threading. But you are right, for the thickness I am working with, it is cheaper. If my material had been like 4 inches thick, then Water-Jet would be cheaper. I'll check into it more. Does Laser leave a Kerf as well? The material is 1/4", 3/8" and 1/2" (1/2 inch for the router mounts) mild steel.


VTX,
Thanks!

I was also thinking about getting everything Powder Coated as well after it's been welded up and sanded. How much do you think I need to add to the bearing surfaces to allow for the thickness of the powder coating? I don't want the bearings to be too tight. I'd have to do this to the Z-Axis and the Y-Axis, as the X-axis just floats off the rails.

Not on a CNC machine, but I've seen the logo... I think it looks cool though! IIRC, with the high powered lasers they use air assist which diminishes the "draft" effect somewhat. I don't think the hardened steel, if it does, goes too deep, though i'd check to make sure.

[ger21]

Okay, I can plan on getting it machined. Shouldn't be that much cash to get it flattened. I should probably change the design just a little to add for the machining. How much, maybe .005 added to it? Like, say, if I have it drawn for 24mm (.945") spacing now between bearing and rail, I should make it .94" ? Or, seeing that the mounting surface is 3/8" thick, maybe just leave it the way it is, since there's plenty of material to take away?

I really have no idea, but my guess would be much more than .005" would be needed.

I'd also either machine after powder coating, or see if they can "mask off" the areas when powder coating.

[Falcon69]

Thanks for the suggestion Ger21. Good Idea. Tough, I'm not sure if you can tape off areas so they don't get powder coat on them. I thought powder coating had something to do with charging the metal with electricity of some sort that attracts the paint, then it's baked on. I'll check on that, but good idea

I've been working on the 4axis. It's based off this design I found here....
http://www.cnczone.com/forums/diy-cn...xis_lathe.html

However, I'm not sure what I would need to do for the gearing. I've designed this so far, each set of gears is a 2:1 reduction. Which would make this a 6:1? Or did I not calculate that right?

I'll be using the same motor, the 960oz 7A one I bought earlier for the other axis'. What reduction do you think I'll need? The heaviest item it will probably be turning (to make a column for interior) is probably a solid Oak Piece 12" dia. x 100". SO a pretty heavy piece no doubt.

Wha's your thoughts? Here's the pic what I have so far....

[bobsch]

However, I'm not sure what I would need to do for the gearing. I've designed this so far, each set of gears is a 2:1 reduction. Which would make this a 6:1? Or did I not calculate that right?

Your calculation is off. With a 2:1 ratio the end result will be 8:1. (1/2 to the third power.)

[jckstrthmghty]

You can most certainly mask off areas you don't want painted. It's done all the time.

Tough, I'm not sure if you can tape off areas so they don't get powder coat on them.

[Falcon69]

Your calculation is off. With a 2:1 ratio the end result will be 8:1. (1/2 to the third power.)

okay, I think I understand. so if i use a 3:1 reduction, and 3 sets of pulleys, like above, then it would be 1/3 to the 3rd power = 27:1 reduction?

So, what reduction would I need for the Lathe? In the link I posted, he has a 46:1 reduction, if i read it right.

[Falcon69]

You can most certainly mask off areas you don't want painted. It's done all the time.

for Powder Coating? That's good to know. I'll have it done that way then. Thanks!

[louieatienza]

okay, I think I understand. so if i use a 3:1 reduction, and 3 sets of pulleys, like above, then it would be 1/3 to the 3rd power = 27:1 reduction?

So, what reduction would I need for the Lathe? In the link I posted, he has a 46:1 reduction, if i read it right.

Don't have too much experience with rotary axis, but I believe, especially the larger the swing you have, you'd want more reduction with steppers to get good angular resolution.

[Falcon69]

I was thinking the same thing Louie.

But, I want to keep within my design perimeter too. I could do a 3:1 reduction with 3 pulley sets. That 27:1 reduction, or I can add a fourth set, that would be (1/3)^4=81:1 reduction, correct? I think that would be too much. If I substitute a 2:1 ration set in there, than how would I calculate that?

(1/3)^3=27:1
(1/27)(1/2)= 54:1 <---- Calculated right?

Now, that would be pretty close to what the guy had in the link I posted above of 46:1 reduction, but he was using a servo motor. Is there a difference between the servo and the stepper? Or do the same calculations apply?

I'm kinda stuck on pulleys that I can use. I want to build this thing with no less than 7/8" shafts. I want to keep this thing stout and beefy. Maybe I'm expecting too much.

[Grunblau]

I'll be keeping an eye on this one. Looks like a lot of the laser fabrication stuff we do....

Couple things FYI... We have had a ton of stuff lasercut and the draft on the edge is really non existent even on 3/8". The kerf is accounted for by the laser company and they usually pride themselves on getting to your CAD specs. We have had one of our companies 'under compensate' on a project where we had a micro puzzle piece zipper joint in 1/8" stainless to insure things would fit, using the laser kerf as tolerance.

Incidently, 3/8" used to be where the cost benefit of lasercutting flipped to favor waterjet. There are angle compensating heads at some waterjet places. If they don't compensate, the angle can be pretty severe.

You need to build in tolerance. It is nice when CAD models 'snap' together, but in the real world, grinding your newly lasercut pieces sucks (trust me).

Find out what steel thicknesses really mic out at. For example, if you ask for '1/8"' steel, chances are it will come in at around .118" thick (at least ours does). There are charts for this showing limits for production of steel sheets. For 11 gauge steel it is supposed to be .1196" but the limits are between .1121" and .1270"

To avoid all of this, I make the slots for our fabrication .125" knowing the actual steel will be .118" I also add a 1/16" at both sides of the slot.

[_[____________]_]

This makes an excellent place to tack the piece together and grind flush. Because the laser beam is essentially a round pierce, the interior corners might have a very small radius. Doing this makes allowance for all interior corners.

It might seem sloppy, but when you are fixturing it up, all of the slots you have sort of take from the tolerance available and everything quickly tightens up. We have send a "conditions' test file to the laser before these are just small tests of the conditions proposed. For $50 you can have piece of mind before spending $2k on 'version 1' pieces.


Some laser companies charge you a per pierce and a per length rate. A huge amount of pierces can greatly increase your price. For example, $2/ pierce and 10 cents/ inch of cutting.

If you had a 1 foot rectangle, this would be $4.80+$2.00(one pierce) = $6.80.

If you had a 1 foot rectangle with a 3x3 grid of holes inside it, the price is now $4.80+$20.00(ten total pierces)= $24.80 + the length of the holes. Just to give you an idea.


As far as the tempering of the hole, this is something I have always wondered about after breaking a few taps. I now drill laser cut holes before tapping, being suspect of that first 1/32". Plasma cutting absolutely hardens the edge.

Looks good so far!

Brian

:cheers:

[Falcon69]

thanks Brian, that cleared up alot. The machine where you had your laser parts cut out, was it a 5-axis that tilted to compensate for the kerf, or is it that 3/8" and less thickness steel, the kerf a laser leaves is not measureable?

[louieatienza]

I was thinking the same thing Louie.

But, I want to keep within my design perimeter too. I could do a 3:1 reduction with 3 pulley sets. That 27:1 reduction, or I can add a fourth set, that would be (1/3)^4=81:1 reduction, correct? I think that would be too much. If I substitute a 2:1 ration set in there, than how would I calculate that?

(1/3)^3=27:1
(1/27)(1/2)= 54:1 <---- Calculated right?

Now, that would be pretty close to what the guy had in the link I posted above of 46:1 reduction, but he was using a servo motor. Is there a difference between the servo and the stepper? Or do the same calculations apply?

I'm kinda stuck on pulleys that I can use. I want to build this thing with no less than 7/8" shafts. I want to keep this thing stout and beefy. Maybe I'm expecting too much.

Well, you'll have far better resolution with a servo, and probably a better power range as well. Then again with all those pulleys, bearings, plate, and shafting, and machining, you could probably just find a good used harmonic drive or planetary gearhead on eBay, and save yourself a lot of work. And it would most likely bolt right on to your stepper or servo.

Brian, some interesting info on laser cutting there...