Gina

It's alright - I think I have it sussed.

I second that!!

Nice.

Has anyone added a cable chain to their 3D printer to support the "umbilical" (set of cables to the X carriage)? I'm trying to work something out for my upgraded Giant printer.

Rough bed levelling is achieved with guitar pegs in the bed corners. Precise bed levelling is assigned to the automatic bed level compensation in the control board.

This first photo shows the main framework of the printer plus print bed Z carriage frame and XYZ drive systems. The external dimensions are 750mm x 660mm x 1000mm. The frame parts are 20mm x 20mm aluminium extrusion designed for wheels to run on. The X rail is wider at 40mm x 20mm for extra precision. The printing capacity will be 490mm x 470mm x 650mm (or maybe slightly more). Most printed parts are PETG with the exception of the Z drive gears which are PLA for the large gear and TPU for the motor pinion. Also, the parts cooler air duct is in ABS for that ability to "solvent weld" it in parts. This printer is different in some ways from most 3D printers. The X and Y drives are combined in an arrangement called CoreXY where one stepper motor provides X+Y motion and the other X-Y motion. The drive is by standard timing belts and pulleys. The Z drive is different - it uses fishing line braided cord which is very strong, with negligible stretch. Cords are attached to the 4 corners of the bed frame, go up over pulleys and onto a horizontal aluminium tube that acts as an axle/drum where the cord is wound up to lift the bed. This is driven by gearing with a 10:1 ratio from the Z stepper motor.

Following on from my Giant Mk 2 printer this version has a number of changes that warrant a new blog.

Think I'll start a new blog as the upgrade make this printer quite different. GinaRep Giant Mk.3.

Bed corner blocks completed and installed plus all four suspension cords connected to the adjusters. Z drive pinion printed, pushed onto motor shaft and motor mounted on main printer frame. On testing by hand it was found that the Z carriage frame collided with the left hand XY motor so a new motor mounting was required. Since the standard NEMA17 bracket wouldn't fit, a 3D printed motor bracket was designed and printed in PETG. With all drive mechanics completed, the printing capacity was measured - 470mm x 490mm x 650mm (XYZ). Still to do :- Decide location and mount control box and hotend cooling water reservoir. Wiring and water tubing. Umbilical support cable chain. Filament reel support.

Printing blocks for the corners of the Z carriage/bed. These have three functions :- Hold the Z carriage frame members together, square and level. Hold the wheels that hold the bed in the right position horizontally. Provide brackets for the bed level adjusters (guitar pegs).

Looking at This Cable Chain. Think I'll design my own...

Aint that du truff!!!

I've printed astro parts in ABS which is softer than PLA and screwed metal parts onto or into the plastic. Just a question of allowing a couple of tenths of a mm interference fit.

Yes, it was very dark in that torrential rain - had to put the lights on to see to do my project - Giant 3D printer upgrade.

Calculate the Z drive parameters :- Shaft diameter = 25.4 mm giving circumference of 25.4 x π = 79.8mm. Motor does 200 x 16 = 3200 µsteps per revolution. µsteps/mm therefore = 3200 x 10 / 79.8 = 401.02. 401 µsteps/mm seems pretty reasonable. That's if I've got the calculation right ?

No, just about a 1" square where the probing points are (I use 9 but I think 4 would be sufficient with a glass bed, which is very flat). Sometimes the models do stick better to the copper than the copper does to the glass but that's mostly when I'm too eager to get the print off before it's cooled down enough.

I use inductive probes but these need metal to work. I use very thin copper foil pads stuck to the top of the glass.

3D printers have come down a lot in price in the last few years. But unless you pay for a good one they take rather a lot of setting up.

Oh yes, they're the "bee's knees"

It's had good reviews... I'll leave it for someone using it to reply. I use the Duet WiFi (the deluxe option!)

I used low voltage (24v rated), high current (16.5A) cable I got from Amazon (I think) for my observatory power. Separate mount and camera lines. eg. *16.5 AMP Rated* 1mm2 Thin Wall 2 Twin Core Cable Wire Car LED Lights but I think I bought it by the metre. You can get low voltage cable in higher current ratings too - useful if you have long runs to reduce voltage drop.

Rear pulley blocks designed and printed in ABS and checked for fit. Final blocks will be printed in PETG. Now working on the Z drive. A horizontal aluminium tube, 1" (25.4mm) OD will go across the top from side to side and centred front to back. This will be driven by a pair of spur gears from a NEMA17 stepper motor. Cords from the corners of the bed will go up over pulleys and be wound up on the tube. There will be approximately 9 turns to raise the bed from bottom (Z = 700mm) to top (Z = 0). With a cord diameter of 0.4mm these turns will take up just under 4mm for each cord. Approximate bed levelling will be achieved with guitar pegs attached to the bed frame - accurate bed levelling will rely on the auto-bed-level-compensation of the controller electronics.

Ah yes. A while ago I made a 3D printed micro-dome for an astro camera plus SLR camera lens for widefield imaging, the rotation was relatively easy but the shutter was a different matter. At that point I put the project on the back burner and got on with other things. I might resurrect the project one day - it's the mad sort of thing I like ? Glad to hear it's still working well. That's the sign of a job well engineered. Congratulations

Really??? It's cloudy here... It's getting ready for the rain...

I'm amazed how accurately you made the drive ring - the sprung motor unit barely moves. Using a router was a brilliant idea. Love it