As posted about before, I’ve been assembling a ZTW 7×12 CNC router. It went together fairly smoothly using the 7×7 manual, but there are a few differences. I’ll outline those differences in each step after the break. The mechanical assembly will also be reviewed. Before all that though, here’s a video of it coming together in not-quite-stop motion:
The 7×7 manual is organized into three sections, Y, X, and Z – in that order. If it doesn’t jump out at you immediately, these letters stand for the different axes of travel. Here are the notes on this manual according to each step:
y-06, 11, 12: Frame part 10, 11 are longer than pictured
Y-13 through Y-18: Same as 7×7 manual
Y-25: Use medium length lead screw (will be around 14 1/4 inch length)
Y-26: Pay attention to alignment
Y-28: Use medium length rods (around 12″ in length) also frame # 11 is larger
Y-40: Screws may be tight in PVC, doesn’t seem to be a problem
Y-46: Pay attention to alignment – slots on PVC part should be towards the back of the machine closest to the stepper motor.
Y-48 through Y-51: Look at step “Y-52″ first. Also, it will be good to loosely install all screws before tightening them down.
Y-55: Pay attention to which side the end holding nut faces.
Y-59: Screwdriver with a thin shaft would be best. Look at “Y-63″ before doing this step.
X-10: Use long lead screw. Length will be about 20 inches. When assembled, if one end is galled, simply screw in from other side
X-12: Use longest rod. Will be around 18 inches
X-14: Use frame part # 6 as well as the parts listed
X-23: Make sure everything is lined up correctly
X-28: Also need frame # 12 (2)
X-34: Screws are medium length – around 1″
X-39: Orient nut correctly
X-43: Look at step “X-44″ for motor orientation
X-44: Tighten set screws on flex coupling
X-45: Thin shaft screwdriver best for this step
X-50: Only 8 screw holes, not 16 as stated in the directions
X-56: Use longest screws. Can use thin pliers to hold nut on inside
X-60: Alignment can be done with calipers if available. Can tap the sides to line them up perfectly.
Z-Axis: (Should be the same as 7×7 kit)
Z-16: Clean rods as in other steps. Ensure screw holes face upwards as shown
Z-18: If things don’t fit quite correctly, don’t force them. Loosen screws and work everything in correctly.
The machine is done at this point. Keep in mind that you’ll have two #1 pieces left over to help you clamp down what you’re working on.
Thoughts on the mechanical setup of this machine:
All in all, this is a pretty easy setup. Priced at just under $400, it represents a great value if one wants to get into CNC controlled machines. This frame is meant to be used with a rotary tool or their own spindle. Although I don’t yet have the CNC controls hooked up yet, I’m excited to see what it can do. Also, they include Allen keys and lots of spare nuts, bolts, and washers.
The frame parts themselves are physically numbered, so they are easily identifiable. The motors look great, and the double set screws on the flex coupling and alignment nut should hold things very securely. The only bad things that I could say about it are that it would have been nice if everything used hex screws as the Phillips head screws tend to strip sometimes. Also, the use of dowel pins in some instances could have made things align more easily. As this unit is priced at $400 and aimed at the hobby market, the unit still appears to be an excellent value. Check back for when I go over hooking up the electrical controls part of this machine (assuming I’m successful at it).
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