Part of the frame assembly (or just after) is to fasten the y-axis motor mount and belt idler. They sit either side of each other at the two ends of the printer frame. This is where this 3D printers starts it’s path away from the standard version and takes on Toolson’s upgraded and improved parts. First up is the motor mount which is two metal plates and a printer plastic part to space them apart. This printed part also acts as a dust guard and stop any dirt and debris from falling on the motor axle and drive gear. It’s the first time you get to fasten something electrical too – a stepper motor!
I have bought a kit of five steppers, standard NEMA17 ones (45Ncm/64oz.inch) from http://www.omc-stepperonline.com/. One thing I am interesting in implementing is adding a layer of vibration, heat and sound proofing between the motor and the frame. I am unsure about how effective this will be, but it seems wrong to bolt a metal plate of a motor to a metal frame with nothing in between? I have read that the vibration dampening can only be improved by decoupling the motor from the frame using a dedicated mount, so I don’t think I will gain anything here. Oh well… lets give it a go!
As you can see, I used some “slip mat” material (the type you put under rugs to stop your granny from slipping and breaking a hip!) and cut it to size. I could have used those cork gaskets that you can buy online, but I didn’t want to buy any. From what I have heard, they help more with eliminating heat entering the frame – but with 3mm steel; i’m not too worried about heat build up… this thing weighs a tonne!
Motor is mounted onto the brackets which are bolted to the frame with the ridge of the plates “pointing up”. The printed plastic part is added in between the two plates to act as a spacer and also acts to keep out dirt and debris from the drive gear and axle.
The build process can also be watched in glorious HD time lapse in the video below. If you like the video, check out some of my other time lapse’s on my YouTube Channel and don’t forget to give them a thumbs up, and subscribe to me!!
Don’t forget to add your belt pulley drive gear. Depending on where the tightening grub screws are on your gears, you may need to fasten this on the motor shaft before you tighten everything up. On mine the grub screws line up (not so) perfectly with the mounting plates, so I can’t adjust it on the fly without dismantling it.
Align the belt drive gear
Once all is secure and bolted in, make sure the belt drive gear is aligned with the opening in the mounting plates. You can see below that it is offset and needs to be adjusted.
Something like the image below should work well! The standard GT2 belt is 6mm in width, and these pulley gear are usually about 7mm in width. You are looking to make sure the belt doesn’t rub on the sides of the mounting plates, so you may need to adjust again once the GT2 belt is on.
Now that the motor is attached, we need to add the y-axis idler bearing. This is what the z-axis belt loops around and allows you to complete the timing belt loop. You will need printed part “P3sTE_MK2_Y-idler_v1_2_r.stl” which is the orange part shown below, along with two MF126 (flange) bearings, a couple of washers, an M5 bolt and M5 nylock nut. You will also need a could of M3 bolts and standard M3 nuts to attached the idler unit to the frame. We use MF126 bearings as they are of similar diameter to the 20 tooth GT2 belt pulleys, and the flange parts if put front to front act as a guide lip for the belt.
Watch the YouTube clip above to see how I assembled the idler. Once built I attached the idler to the frame with two of my black M3 bolts into the pre secured M3 nuts embedded in the part.
You can see in more detail the flange of the bearings acting as a lip for where the belt will sit. Give the bearings a flip with your finger – they should rotate freely in their mount. The M5 bolt isn’t fully required, as the plastic housing part designed by Toolson actually has two lips inside which can hold the bearings in place. The bolt is there for piece of mind and to secure the bearings in there.