Saturday, February 15, 2014

CNC Router

I took a little break from working on WALL-E this week and looked into ordering parts for the CNC router I would need. At this point, I've decided to go ahead and use the ShapeOko 2 to fabricate most of my pieces. The reason I've waited this long to decided on a CNC router was because I wasn't sure what the cutting area requirements would have been. Now that I've modeled most of my larger pieces, I would need a cutting area of at least 18"x18". This means that I will have to upgrade my ShapeOko 2 to have longer X and Y axes.

I went ahead and began creating a BOM for the ShapeOko. The mechanical kit, which consists of only the hardware and fasteners, costs $299 while the complete kit, which includes everything you need to get started, costs $649.

In order to upgrade my X and Y axes, other parts such as the stepper motor and drivers needed to be upgraded to handle the higher loads. So, I've decided to purchase the mechanical kit and purchase the rest.

As it stands, my ShapeOko 2 without the cost of cutting bits will costs around $915 including tax and shipping.

The BOM is as follows:

ItemPart NumberRetailerQtyUnitUnit CostQty CostShippingTaxSubtotal
ShapeOko 2 Mechanical KitInventables11$299.00$299.00$29.33$0.00$328.33
MakerSlide 1000mmInventables41000m$21.84$87.36$0.00$0.00$87.36
GT2 Pulley26054-02Inventables31$6.47$19.41$0.00$0.00$19.41
Spacer, #12 X 1/4Inventables210$2.61$5.22$0.00$0.00$5.22
GT2 BeltInventables81ft$1.99$15.92$0.00$0.00$15.92
Terminal BlockInventables41$2.50$10.00$0.00$0.00$10.00
M3 Hex Nut8$0.00$0.00
Cap Screw, M3 X 12, SKT HDInventables110$2.14$2.14$0.00$0.00$2.14
Cap Screw, M3 X 8, SKT HDInventables210$2.09$4.18$0.00$0.00$4.18
Cap Screw, M5 X 20, BTN HDInventables210$2.35$4.70$0.00$0.00$4.70
Midspan SupportShapeOko1$40.00$40.00$5.00$3.20$48.20
DDW660 MountShapeOko1$15.00$15.00$5.00$1.20$21.20
NEMA 23 Stepper Motor (156 oz-in, 1/4 shaft)KL23H251-24-8BATI3$15.95$47.85$13.33$0.00$61.18
NEMA 17 Stepper Motor (76 oz-in, 5mm shaft)KL17H248-15-4AATI1$12.99$12.99$0.00$0.00$12.99
Stepper Breakout BoardKL-DB25ATI1$28.04$28.04$0.00$0.00$28.04
Power Supply (24V, 14.6A)SE-350-24Jameco1$44.95$44.95$7.30$3.46$55.71
100 uF Capacitor29962Jameco110$1.20$1.20$0.00$0.00$1.20
Pololu DRV8825 DriverDRV8825Pololu4$13.95$55.80$5.95$0.00$61.75
Stepper Motor HeatsinkPRT-11510Sparkfun4$1.95$7.80$3.93$0.00$11.73
Thermal AdhesivePRT-09771Sparkfun1$3.95$3.95$0.00$0.00$3.95
Router Speed Control43060Harbor Freight1$19.99$19.99$0.00$1.60$21.59
Aluminum Extrusion 20mm Inline 6ft5537T117McMaster Carr1$17.19$17.19$0.00$1.38$18.57
Aluminum Extrusion 20mm Inline 8ft5537T117McMaster Carr1$21.58$21.58$0.00$1.73$23.31
M3 Flat Washer93475A210McMaster Carr1100$1.62$1.62$0.00$0.13$1.75
M5 Flat Washer93475A240McMaster Carr1100$2.57$2.57$0.00$0.21$2.78
M5 Hex Nut90591A146McMaster Carr1100$2.08$2.08$0.00$0.17$2.25

This final cost is assuming I group orders where possible to avoid additional shipping charges. I could in theory reduce the cost a bit if I don't purchase the DW660 mounts (I think I've seen them mounted for cheaper) and if I don't purchase the router speed control which may not be necessary. Some small fasteners I may be able to acquire from work or school and if I'm really lucky, I may be able to machine the midspan supports myself at school.

So, the price range I'm looking at is around $824 to $915, but to be honest, I'll probably end up purchasing everything in this list... :)

I went back and added some additional components to purchase to account for almost everything I'll need. I've added a 5V regulator (along with the necessary capacitors, inductors, diodes, and heatsink) for the stepper drivers and breakout board, 2cm long headers for the stepper, right angle brackets and hardware for the t-slotted extrusions, and some 18AWG 4 conductor wire for the stepper motors. I've also sourced some hardware I was originally going to buy from Inventables to Jameco and McMaster Carr to save a buck here and there.

The only things left to add to the BOM are the hardware to mount the terminal blocks (which I can probably find somewhere instead of buying), the hardware to attach the heatsinks (which I might end up just using the thermal adhesive), and the cutting bits.

I looked into the speed controller a little bit and it seems to be a toss up on whether or not I should use one. I suppose that these routers and cut-out tools weren't designed to be used with a controller (but it doesn't mean it can't be used with one) but I'll hold off on buying that for now.

So, the total cost now stands at $940.36, of which $69.13 is shipping and $21.25 is tax. To be honest, the shipping costs were all very reasonable for the amount I was buying and luckily I wasn't charged tax on many items.

Now comes the hard part of deciding whether or not to start buying everything... 

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