Sunday, March 29, 2015

OX Build - Part 5

Related: Unboxing, Part 1Part 2, Part 3, Part 4Part 6Clamps

I decided to tackle the spoilerboard next. I debated several options and decided to try something call slotwall. I bought a 4x8 sheet of slotwall and some sheets of 1/4" and 1/8" MDF to use as the real spoilerboard.

I've found that the MDF is extremely flat and I'd prefer to ruin small little pieces rather then the slotwall.

This is what the profile of the slotwall looks like:

All of my woodworking jigs use 1/4"-20 hardware, so I decided to use that for my holddowns. I used 3-pronged Propell nuts along with a printed piece to make my T-nuts:

I wound up putting a recess on the bottom and used support:

This was removed quite easily. In hindsight, I probably could have made the T-nut a bit thinner and not needed support.

Here's the propell nut installed:

And how it fits in the slotwall:

Installed:

Oops. I didn't quite center the slotwall. The left most slot just clears the corner bracket, but the right most slot needed a wee bit of "adjustment", which was done with a file:

The OnShape document can be found here.
The STEP and STL files are here.

Related: Unboxing, Part 1Part 2, Part 3, Part 4Part 6Clamps

OX Build - Part 4

Related: Unboxing, Part 1Part 2, Part 3, Part 5Part 6Clamps

Now that the basic mechanical stuff is done, it's on to the electronics.

I had some surplus cable chains that I salvaged off another machine, so the first order of business was to create mounts for them. Right around this time, I also discovered onshape.com which is a free online solid modelling CAD site. You need to request a beta invite. This took a day for me, but other people I've talked to have gotten their accounts activated fairly quickly.

In the event that any of the 3 printed parts are useful to someone, I'll be making all of the parts public under OnShape, and will provide URLs to the parts, to STEP files, and to the STL files. I'll put a table with links to all of the 3D printed parts at the end of the post.

This is the lower X cable chain mount. This fits in the V-Slot.


The upper X cable chain mount (goes above the stepper):

Here's the X cable chain mounted:

For the Y cable chain, I wanted something to support the cable chain. I used two pieces of 90 degree trim pieces I found at Home Depot. This is the mount I designed:

This is what the 90 degree angle pieces look like (they're about 3/4" on each side):

The 90's fitted into the mounting piece:

And the Y cable chain support in place:

This is the upper mount for the Y cable chain:

With the cable chain attached:

And the lower mount. Since this is near the middle of the support, it also helps to hold the 90 degree channels together as well.

 Gantry all of the way back:

Gantry all of the way forward:

The cable chain for the Y axis was Igus Zipper chain, so one of the sides is removable, which makes putting the cable in a bit easier:

I printed a temporary mount for the TinyG board (I'll eventually use a metal enclosure). The 4 holes in the middle will mount on the rear of the gantry.

And the upper portion allows for a 12V 80mm cooling fan. The cooling fan should really blow onto the back of the board, and I'll move things around when I build the metal enclosure.

The speed controller had a couple of places that looked like they could be used for mounting holes, so I tapped them for M3:

This is the mount for the speed controller:

I also created some T-nut keepers, so I could put some extra T-nuts in the slots nd not have them make vibration noise:

This shows some of the T-nut keepers in use:

Everything all wired up:

Closeup of the left Y stepper:

And the right Y stepper:

The top of the X cable chain. I left a piece of string in the cable chain since I still have more wires to pull through (this cable chain didn't have the "zipper" feature). I used a zap strap to keep the cable loom from fraying and then wrapped it in heat shrink.

Here are some wire clips I designed. The one on the left is secured to the V-Slot using an M5 screw. The one on the right snaps into the V-Slot:

Here's an example of the screw mounted version:

An the clip on version:

Closeup of the stepper wiring. From left to right is Motor 1 thru 4, X, Y1, Z, and Y2. I wired the NEMA 23 motors (X, Y1, and Y2) all in the same order. For some reason, the NEMA 17 use different colors for the coil pairs, which is why its different.

I designed a pen mount, and this is a photo of the pen mount, along with the output of the first gcode file run:

Video clip showing the first gcode run using ChilPeppr:

I set the rapids to 400 mm/sec (24000 mm/min) and here's a video showing corner to corner moves. That was just my initial guess at a rapid speed, I'll need to play to find out how fast it can actually go.


3D Printed Parts

OX-Cable-Chain-MountsOnShapegithub (STEP & STL)
Spindle-Driver-MountOnShapegithub (STEP & STL)
TinyG-MountOnShapegithub (STEP & STL)
Wire-ClipsOnShapegithub (STEP & STL)
T-Nut-KeeperOnShapegithub (STEP & STL)
Pen-HolderOnShapegithub (STEP & STL)

Related: Unboxing, Part 1Part 2, Part 3, Part 5Part 6Clamps

Monday, March 16, 2015

OX Build - Part 3

Related: Unboxing, Part 1Part 2, Part 4Part 5Part 6Clamps

After getting things together up to the end of Part 2, I think that things should be assembled in a slightly different order.

I didn't tighten the screws down on my delrin nut because I wanted to do it with the leadscrew installed. I found working on the Z axis to be alot more difficult than it needed to be, just because it was mounted on the gantry.

So I think that the entire Z axis assembly should be assembled first, then mounted on the gantry extrusions and screw the whole thing down.

I had issues getting my leadscrew to go through the delrin nut. I could start it, but couldn't seem to get it to go all the way through. Looking into the nut I could see pieces of swarf still floating around:


I removed what swarf I could see with a pair of tweezers. Then I was able to get the leadscrew through, and a bunch more swarf came out:

I then ran the leadscrew through several more times. This is a shot of what came out (not including the bigger pieces I pulled out with the tweezers:

Remove the delrin nut and put it on the leadscrew. You'll need to install the upper bearing and the locking collar first. Leave the 3 screws which mount the plate stepper plate to the extrusion slightly loose. Leave the 2 nylock nuts in the delrin nut (they should be on the side facing the extrusion).

Slide the extrusion into place:

Line up the holes and put the leadscrew nuts in place. Tighten them up almost all the way, but leave them just a wee bit loose.

Now turn the leadscrew so that the extrusion is as close to the stepper end a possible, without actually touching the black mounting plate. Tighten up the screws on the mounting plate, taking care to keep the straight edge of the black plate parallel to the face of the extrusion. You're also looking to have the leadscrew parallel with the back of the extrusion. This is the black edge I was talking about:

I found that looking through the holes between the mounting screws, you'll be able to see part of the extrusion. In my photo below, none of the extrusion was visible.

Now put the bottom black plate on and move the extrusion up (by rotating the leadscrew) until the bottom plate is almost touching the front plate, and tighten up the screws.

Make sure that the bearings fit into the recess in the black plate, and secure the lock collar. Make sure that they is no play between the lock collars and the bearings.

Now you can remount the z axis assembly on the extrusions and mount the extrusions.

I verified that the front of the z-axis was sqaure with the bed while tightening the screws up.


Time for the belts. I filed the ridges off the edges of the bolts that were going to be used to securing the belts. With the ridges things tend to move as the screws are tightened.

I found the easiest way to hold the screws while filing the ends was to put the screws in my allen wrench and then hold the screw with my thumb and finger while my hand was wrapped around the allen wrench:

I also didn't like the screws clamping directly on the belts. I had some Simpson Strong Tie metal plates that were about 0.036" or 0.9mm thick).

I cut a piece about 5mm wide and the same width of a T-nut.

I put these between the T-nut and and the belt, so that the screw was clamping on the metal shim instead of directly on the belt.

The instructions use drop in nuts for the X axis belt, so I did that, but I think I would have preferred to use the regular T-nut and shims.

I'd like to put belt tensioners on all of the belts, so then this will be pretty much a moot point.

Tip: don't use ball end allen wrenches for tightening up the grub screws.

I twisted one of mine right off. I could move it around but couldn't get it out. Even gravity wasn't being helpful. Then I tried a stack of rare earth magnets and they pulled it right out (phew):

Brandon (from smw3d.com) asked me to check my speed controller (since he was going to be sending me replacement bearings - apparently somebody else had a speed controller that went bad.

I wired everything up:
 

And pluugged it in. The spindle would start turning and immediately stop. The power supply seemed to be cutting out.

Doh:

I had checked the 24V supply when I unpacked everything but neglected to check the 48V supply, and it was set to 230V.

I changed it to 115V:

and lo and behold, it worked!

I took a video of the Quiet Cut spindle:

 And also from my Bosch 1619EV router that I use for normal woodworking:

That's it for this part. Next will be the wiring.

Related: Unboxing, Part 1Part 2, Part 4Part 5Part 6Clamps