Commit eb238b86 authored by Jake Read's avatar Jake Read

doc oclock

parent 632e9a8b
......@@ -259,8 +259,6 @@ Now, I'm not going to try to relay exactly what I did - you can take a look at t
- Tool Libraries, Feeds, Speeds Calculator
- Path Type Selection
I go to the CAM section right away, and setup some stock. First thing, our Shopbots are setup in Inches, so check that in the 'units' in the top of the tree. I'll use a 0" offset on top of the model, 0.05" on the bottom (then we can be sure to cut through later on) and a 0.75" offset on the sides - I want to be sure to clear the screws I'll be using to fixture my HDPE sheet.
For tools, I set up with a 1/8" 'O-Cutter' - as in, one flute. This is going to be my detail workhorse - it'll cut teeth and holes. I also have 1/4" O-Cutter to do profiles and cutouts. My two other tools are a Chamfer Endmill, used for, well, the chamfers, and a 1/16" 2-flute endmill for some detailing on the pinion. Here's a quick table of the tools, and their feeds and speeds. I used [the CBA Feeds and Speeds Calculator](https://pub.pages.cba.mit.edu/feed_speeds/) to ballpark these, and I'll dial them in as I test the first axis.
......@@ -269,10 +267,6 @@ A note on plastics - TODO heat, why single flute, sharp bits, what chips should
## Milling
I finished all the milling.
![good-job](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/good-job.gif)
#### HDPE:
Type | Flutes | Diameter | What For | Feed, XY (IPM) | Feed, Plunge (IPM) | Spindle Speed (RPM)
......@@ -299,8 +293,6 @@ Fly Cutter* | 2 | 2 & 3/8" | Facing the Bed | 130 | 50 | 6500
* I used a 1.5" stepover, and ~ 0.03" stepdown. I set the facing pattern up to only cut on the 'climb side' of the bit - that was pretty critical. I think it's possible to be more aggressive - the bit we have at the CBA is quite dull. The job ran about ~50 minutes.
## Doing the Milling
![milling teeth](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/milling-teeth.gif)
......@@ -313,14 +305,92 @@ These are the chips you want. Machining plastic should be impressively smooth, s
This is the chip-fountain you want:
![the-fountain](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/the-fountain-you-want.jpg)
![the-fountain](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/the-fountain-you-want.gif)
In time (est. 1 full day, at least!), I finished all the milling.
![good-job](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/good-job.gif)
## Assembly
- Careful on Blocks! Trim and Align
So I get all of the bits together, and clean the edges up where I need to with a Deburring Tool & regular old knife.
![assembly-debur](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/assembly-debur.jpg)
I started with the X/Z Block, tapping the guideblock's back-side. With tapping plastics, I normally just chuck the tap in a drill. Careful to go in straight, though!
There's a subtlety to putting the glideblocks together. The M5 SHCS goes through three layers - this is not common / encouraged in 'precision' machine design, because there is some uncertainty about how exactly the layers line up.<sup>aside, motor concentricity</sup> Critically, the middle block (the one with the chamfer) is a *very slight* slip-fit (5.1mm), the outer block is a large slip (5.4mm) and the final block is threaded. ALSO: Don't forget a washer!
![assembly-guideblock-hardware-stack](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/assembly-guideblock-hardware-stack.jpg)
I got two sides together to test it oot:
![assembly-slide-test](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/assembly-slide-test.jpg)
There's a reason one side of the glideblocks is mounted on a slot - this way you can adjust the spacing between the blocks - which is important! This way we can slide the gantry over the rail and then *tune* the stiffness.
![assembly-gantry-adjust](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/assembly-gantry-adjust.gif)
OK, there's the block, ish
![assembly-xz-no-motors](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/assembly-xz-no-motors.jpg)
Now I'm going to get some Set Screws tapped into the Pinions, and try mounting motors to this block. M4 Tap Drill Size is 3.3mm, (TODO: Link Chart), so a #30, so a 0.1289", etc
![assembly-tapdrill-select](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/assembly-tapdrill-select.gif)
Same drill here for the hole-tapping<sup>pun</sup>. This time, M4.
To get the pinion teeth in the right spot w/r/t the rack, there should be about 24mm between the motor flange and the top of the pinion. Check this against the actual machine. Also, make sure one of the set screws is aligned with the 'D' cutout on the motor shaft.<sup>note on bearing->load distance, slocum</sup>
![assembly-pinion-d](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/assembly-pinion-d.jpg)
Now I get the motor on the motor-plate - countersinking the M5 FHCS<sup>flat head</sup> into the plate. This way, the plate can ride flush against the rest of the gantry.
- pic, motor on plate
And mount that on your gantry. I used those plastic self-tapping screws here. AND I left them a bit loose. You'll notice that the motor slides, also, relative the gantry:
- gif, motor and plate on gantry, sliding.
Adjustment: it's a theme.
Now, I got a good look at my pinion -> rack engagement. Feeling good about this, so I celebrated with a [knoll](https://www.youtube.com/watch?v=s-CTkbHnpNQ). Nothing like it.
- pic, knolled
To get the rest together, I'm using a 1/8" drill diameter to pre-drill for these plastic screws, and then driving them in with a T20 bit. In addition to this, I don't screw them all down 'in sequence' - I add screws kind of sporadically to the structure - this way I don't pre-stress it in any particular direction. And make sure to use washers!
* a note on rigidity / 'deep' structures - here's the frame w/o any boxiness:
- gif, flappy frame
and with
- gif, rigid frame
OK - I got it all together - the axis just slide together once they're set up. At this point, you'll want to adjust the position of your motor, and of the 'second rail' to get smooth motion.
## Ways Adjustment
## Plugging in Motors
I made no concessions for wiring while I was designing - if you're going to 'rev' the machine I did, please do this! If not, do a bit of planning for your wiring. Just a bit. This part tends to be super-stochastic... My strategy is to drill holes where I want to mount wires, and loop zip-ties around them, in bundles, there.
I got lucky and had accidentally spaced my bed-rails at the pitch of some mount holes on the Power Supply. Rad.
- pic
I mounted those, and the TinyG. To bring power to the PSU, I cut up a DIN connector and plugged the GND, Line and Neutral lines in like so:
- pic
The TinyG gets power here - polarity should be obvious. Obviously, you should be being safe and not turning anything off yet! Careful with the TinyG polarity - it will die if you reverse these.
Next, I drilled some holes in the chassis for my motor wires. I also found this rad 4-conductor cable in the basement at the CBA, I'll use that to route out to my motors.
- Coils are connected
- One and two
- Link Datasheet from StepperOnline
......@@ -334,6 +404,11 @@ This is the chip-fountain you want:
- Now complete setup
- Open in a serial terminal (Arduino has one built in, or see Neil for links) TODO
45.045 mm/rev
eighth microstepping
- make sure y axis are flipped relative
- motor wiring is dependent on ur business
![its alive](https://gitlab.cba.mit.edu/jakeread/machineweek/raw/master/images/axis-moving.gif)
## Chilipepper
......
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