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Re: Hardcoat OpenRail

Posted: Fri Mar 07, 2014 12:10 am
by Improbable Construct
You really do not have to convert the Y axis.
It does not take the twisting axial loads that the X and Z axis take.
I am running Makerslide and delrin V wheels on my Y axis and it is still not the weakest point in my set up.
Getting the X solid and then the Z are the two biggest performance upgrades.

Re: Hardcoat OpenRail

Posted: Fri Mar 07, 2014 12:39 am
by cvoinescu
danimal wrote:I used .25 aluminum plate for my new carriage plates. It feels roughly the same weight, but more rigid than the laser cut stainless.
Some aluminum alloys, depending on temper, can be as stiff as mild steel, but, as a rule of thumb for the more common alloys, aluminum needs to be one and a half times the thickness of steel to be as rigid. So your 0.25" of aluminum beats the 14 gauge (0.0781") steel plates of the original Shapeoko hands down. The rigidity of a plate is proportional to the cube of the thickness, so your plates are about ten times stiffer than the originals, and stiffer than even the very heavy Shapeoko 2 plates.

Re: Hardcoat OpenRail

Posted: Fri Mar 07, 2014 3:43 am
by danimal
cvoinescu wrote:
danimal wrote:I used .25 aluminum plate for my new carriage plates. It feels roughly the same weight, but more rigid than the laser cut stainless.
Some aluminum alloys, depending on temper, can be as stiff as mild steel, but, as a rule of thumb for the more common alloys, aluminum needs to be one and a half times the thickness of steel to be as rigid. So your 0.25" of aluminum beats the 14 gauge (0.0781") steel plates of the original Shapeoko hands down. The rigidity of a plate is proportional to the cube of the thickness, so your plates are about ten times stiffer than the originals, and stiffer than even the very heavy Shapeoko 2 plates.
I am not sure on the alloy, but I think that it is 6061. It was in a pile of 6061 plates and pieces at the scrap yard and I paid $10 cash for the roughly 24" x 36" x .25" plate. Scrap yards are where its at for metal pieces.

Re: Hardcoat OpenRail

Posted: Fri Mar 07, 2014 5:05 am
by benjamd
Improbable Construct wrote:You really do not have to convert the Y axis.
It does not take the twisting axial loads that the X and Z axis take.
I am running Makerslide and delrin V wheels on my Y axis and it is still not the weakest point in my set up.
Getting the X solid and then the Z are the two biggest performance upgrades.
That's interesting...makes sense I suppose. I'm upgrading my Shapeoko 1 to a 50cm 40x40 X axis and 1m Y axis shortly. I noticed your X axis appears to have been upgraded to 80x40, did that make much difference over 40x40?

Re: Hardcoat OpenRail

Posted: Fri Mar 07, 2014 1:24 pm
by Improbable Construct
benjamd wrote:
That's interesting...makes sense I suppose. I'm upgrading my Shapeoko 1 to a 50cm 40x40 X axis and 1m Y axis shortly. I noticed your X axis appears to have been upgraded to 80x40, did that make much difference over 40x40?
Yes it did!

Re: Hardcoat OpenRail

Posted: Fri Mar 07, 2014 3:01 pm
by Llamas
You're only saying that because I just received my 700 mm 4040 piece to upgrade from 500 mm! At least you haven't done anything to make me feel inadequate about the speed of my Z-axis.

I'll be attaching some of the hardcoated rails that require drilling into the extrusion. I will report back on how that turns out.

Sent from my SAMSUNG-SGH-I317 using Xparent BlueTapatalk 2

Re: Hardcoat OpenRail

Posted: Fri Mar 07, 2014 3:39 pm
by Improbable Construct
Llamas wrote:You're only saying that because I just received my 700 mm 4040 piece to upgrade from 500 mm! At least you haven't done anything to make me feel inadequate about the speed of my Z-axis.
:lol:

Re: Hardcoat OpenRail

Posted: Fri Mar 07, 2014 5:04 pm
by samc99us
I went with HFS5-4060 x 1000mm for my X-axis. Seems pretty solid, and is the largest section that will fit in the SO2 motor plates without modification.

My biggest concern is with the z-axis, mounting the spindle and getting reasonable travel. If you look at IC's setup, he has the rail mounted ~1" below the x axis carriage, but his x-axis is higher off the work piece. Trouble is he mounts his Dewalt 611 roughly 1.5" below the lower router mount ring, so a fair amount of the router/spindle is unsupported by the mount. The stiffest setup places the router mount right at the bottom of the router, and on the bottom of the z-axis carriage plate, but this requires lowering the z-axis rail basically to the top of the part you are cutting to get full depth of cut travels, and hence your clearance is very low! So in reality, even though I increased the length of my z-axis by 50mm, I don't have any extra z-axis travel if I want to maintain rigidity with the SO2 z-axis design! If you take a look at the Joes 4x4 CNC Z-axis setup, you'll see they move the rail with the spindle, so the entire spindle is well supported during travel. Part of me wants to flip the SO2 setup around, so the spindle mounts to the makerslide, the z-axis carriage is mounted to the x-axis and the z-axis motor+makerslide+spindle move as one unit. This would let you more rigidly support the spindle, but I'm probably missing something.

Edit: I know my proposal sounds like moving in the direction of the old SO1 design, and it may limit your total pocketing clearance, so probably not worth it. I guess the real question is, how far from the collet are you willing to support your spindle?

Re: Hardcoat OpenRail

Posted: Sun Mar 09, 2014 2:03 am
by cvoinescu
samc99us wrote:So in reality, even though I increased the length of my z-axis by 50mm, I don't have any extra z-axis travel if I want to maintain rigidity with the SO2 z-axis design! If you take a look at the Joes 4x4 CNC Z-axis setup, you'll see they move the rail with the spindle, so the entire spindle is well supported during travel. Part of me wants to flip the SO2 setup around, so the spindle mounts to the makerslide, the z-axis carriage is mounted to the x-axis and the z-axis motor+makerslide+spindle move as one unit. This would let you more rigidly support the spindle, but I'm probably missing something.
I don't think you're not missing anything, and I'm glad to see that someone else (besides me) thinks that the Shapeoko 2 Z axis arrangement may not be an unalloyed good after all.

It has some advantages: the non-moving Z rail does not reduce vertical clearance, the Z does not have to lift the stepper, and the inertia of the Z stepper does not add to the load on the Z V-wheels when the X or Y accelerate.

It also has some disadvantages: it weighs more, the spindle is slightly further out from the X axis, there are clearance issues with tall spindles (which can be solved by moving the spindle even further out), and, most importantly, the leverage of the side cutting forces over the Z wheels is less advantageous. There is almost no difference when the spindle is down, which is the worst case for the Shapeoko 1; but in the Shapeoko 1, the leverage improves as the spindle moves up, whereas in the Shapeoko 2 it stays the same. The Shapeoko 2 Z is much stiffer than that that of the Shapeoko 1 only because of the longer wheel base and thicker motor and carriage plates. With the Shapeoko 2 motor plates and wheelbase, the Shapeoko 1 configuration would be even more rigid.

I am no longer considering adopting the flipped Z for the eShapeoko.

Re: Hardcoat OpenRail

Posted: Sun Mar 09, 2014 5:22 am
by danimal
cvoinescu wrote:
samc99us wrote:So in reality, even though I increased the length of my z-axis by 50mm, I don't have any extra z-axis travel if I want to maintain rigidity with the SO2 z-axis design! If you take a look at the Joes 4x4 CNC Z-axis setup, you'll see they move the rail with the spindle, so the entire spindle is well supported during travel. Part of me wants to flip the SO2 setup around, so the spindle mounts to the makerslide, the z-axis carriage is mounted to the x-axis and the z-axis motor+makerslide+spindle move as one unit. This would let you more rigidly support the spindle, but I'm probably missing something.
I don't think you're not missing anything, and I'm glad to see that someone else (besides me) thinks that the Shapeoko 2 Z axis arrangement may not be an unalloyed good after all.

It has some advantages: the non-moving Z rail does not reduce vertical clearance, the Z does not have to lift the stepper, and the inertia of the Z stepper does not add to the load on the Z V-wheels when the X or Y accelerate.

It also has some disadvantages: it weighs more, the spindle is slightly further out from the X axis, there are clearance issues with tall spindles (which can be solved by moving the spindle even further out), and, most importantly, the leverage of the side cutting forces over the Z wheels is less advantageous. There is almost no difference when the spindle is down, which is the worst case for the Shapeoko 1; but in the Shapeoko 1, the leverage improves as the spindle moves up, whereas in the Shapeoko 2 it stays the same. The Shapeoko 2 Z is much stiffer than that that of the Shapeoko 1 only because of the longer wheel base and thicker motor and carriage plates. With the Shapeoko 2 motor plates and wheelbase, the Shapeoko 1 configuration would be even more rigid.

I am no longer considering adopting the flipped Z for the eShapeoko.
I did a ton of static calculations for the torque forces applied about the x and z axis when designing my new z axis. A very small change in distance results in a large change in force that is amplified it terms of end mill tip deflection. I tried to keep everything as close to the axis as I could.

Also something else regarding samc99us's concerns. It is possible to design the spindle mount to sit on the absolute lowest position of the z axis and grip the very lowest point of the spindle. This is a best of both worlds scenario because you gain the general rigidity for most standard tasks, but then when the deep pocket situation does occur, you can slide your spindle down, displace your x axis upward and still have a very rigid setup that will do as deep of pockets as the spindle can do. This only works for easily adjustable systems, that is why I chose the spindle and mount that I did, the RT 0701C is cylindrical and to adjust it down I loosen one M5 screw and slide it down. I think I have roughly 60mm of spindle adjustment if I need it.