I made a slight error when designing the base, I put some screw holes where they foul other screws.
This it not an issue, it will work fine without the two that foul others.
Don't use the marked holes.
From the CD/DVD Drive I also savaged two 3mm diameter polished linear bars, 94mm long.
I have not made anything special to hold this bar in place, I have relied on it being a firm fit.
I have found an alternative if needed, to the 3mm bar on eBay: 3mm stainless round rods.
These are rough finish and need polishing using P200 grit paper. (need to be polished smooth for the plastic to slide freely along it.)
The X Axis that fits on the above bar needs to be a good fit, but slide freely.
The tubular part of the X Axis is hollowed in the centre so care is to be taken if you need to ream it out with a 3mm drill.
Here is a sketch sowing a section through it:
I found that if you get the bar fitted in firmly, then slide the piece back and forth along the bar very quickly, it creates friction, warming the plastic at the points of contact.
Do this until the plastic feels soft, then let it cool with the bar in place. It should make a perfect fit.
The X Axis should slide along the bar freely but with no lateral moment.
The other end need to be smoothed so it will slide along the guide on Part 2 of the Y Axis with very little vertical movement:
Before fitting the X Axis make sure the X Axis bar fits ok:
It is very easy to melt the components of these type of motors with the soldering iron.
I recommend using extra flux when soldering these terminals, speed is important, too slow and the heat will melt the coil bobbin.
Also to help not melting the components I recommend just cutting the ribbon short and soldering the wires on top of what remains.
I use 4 core ribbon cable with a DuPont socket on the end.
The cable length for this motor needs to be about 95mm long.
The cable length for the second motor needs to be about 170mm long.
I only used two M1.5mm self taping screws diagonally to fit the first motor to the base, do not tighten the screws at this time, leave them slack enough for the motor to move side to side slightly.
Fit the X axis and bar, then fit the Y Axis part 2 to Y Axis part 1 using only two screws.
Carefully move the X Axis piece along the length of the motor screw-drive to align the stepper motor, then tighten the screws firmly, not too tight. If the stepper motor is aligned correctly the stepper motor screw-drive should turn, not skip when you move the X Axis along the length of the screw-drive. (you may find you need to back off the screws slightly so they just grip the motor frame)
The Z Axis piece is similar to the X Axis piece.
The X Axis bar needs to be a good fit but move freely, the tube part that the bar goes through is hollowed out like the X Axis piece.
The lower part needs smoothing so it slides freely along the X Axis piece with very little lateral movement.
Also before fitting make sure the Z Axis bar fits ok.
Fitting the X Axis to the Y Axis is similar to fitting the Y Axis to the Base.
Only used two M1.5mm self taping screws diagonally to fit the second motor to the Y Axis, do not tighten the screws at this time, leave them slack enough for the motor to move side to side slightly.
Fit the Z Axis and bar.
Carefully move the Z Axis piece along the length of the motor screw-drive to align the stepper motor, then tighten the screws firmly, not too tight. If the stepper motor is aligned correctly the stepper motor screw-drive should turn, not skip when you move the Z Axis along the length of the screw-drive. (you may find you need to back off the screws slightly so they just grip the motor frame)
A Tip on getting the Plastic Thread to fit perfectly to the Screw Drives.
Adding a little heat to the Screw Drive (just enough to soften the plastic) and pressing the plastic thread to the Screw Drive, wait for it to cool.
Making the parts fit the Screw Drive perfectly, makes every thing work smother and better.
Best to fit the Servo (SG90) next.
The servo needs a single Arm (horn) set so that it is up when moved fully anti-clockwise.
The Arm (horn) is down when moved fully clockwise.
The image shows it set mid way:
The next part is the Tool Holder:
This need to move freely on the Z Axis bar. Also inside the guide needs to be free of debris, so that the Arm of the Servo will move inside freely.
There is also a spring over the bar above the Tool Holder to keep pressure on the Tool Holder.
The spring needs to be a fairly week spring, it just needs to give enough pressure to make a pen fitted work. (remember these stepper motors are quite week and can stall easily)
As a guide, the wire thickness of the one I have used is 0.3mm.
The Servo Arm not only lifts the Tool Holder, it also prevents the Tool Holder from rotating about the Z Axis Bar.
Now fit the Pen Holder and Pen Holder Screw:
Next will be to fit the Circuit Boards.
To be continued
If you are making this and want more information, leave a comment and I will continue.
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