Very nice bit of work. I have been thinking of doing something very similar. However I was going to put the drive motor where you have the tensioner. The drive motor having a 20 tooth pulley, and the shafts having 24 tooth pulleys. This means that the motor steps would not have to be altered.
Your pictures have fired up my enthusiasm!
I left the motor outside of the frame to preserve the full build height. ( i still have 210mm with my E3D V6)
And as it drives the left shaft directly the tooth count of the pulleys is not much relevant,
as long as they are quite the same in diameter.
Stretched K8200: Kit with all parts to convert stock K8200 into 40x20x20cm capable 3D-printer (to print shoes, boats, etc…).
Still working on this add-on. Will be shown at HK Electronics Fair Autumn Edition for the first time.
I was planing to make the stretch mod myself, so my Dual-Z mod uses no belt, but two steppers as this will be easier to upgrade. Second stepper is reversed and hangs upside down on the back side of the printer. Two Trapezoid Z-Spindles from Velleman used and the print results are amazing and comparable to a 2000 Euro printer.
I just chose the “belt driven” version to eliminate the possibility that the 2 motors loose sync.
If working with a 2 motor setup it is easily possible that on of them skips or looses steps, so the
axes no longer run synchonus.
The belt version simply and absolutely prevents this.
I just chose the “belt driven” version to eliminate the possibility that the 2 motors loose sync.
If working with a 2 motor setup it is easily possible that on of them skips or looses steps, so the
axes no longer run synchonus.
The belt version simply and absolutely prevents this.[/quote]
Never had a sync loss yet, but it is true. With my setup the motor has only half of its strength. None of other 3D printers with 2xZ-Spindle don’t have sync losses and use similar setup.
Hello, it is a very nice mod you made. I want also use a second z-axis for my k8200. I found on thingiverse a similar solution by cypax. He use only one toothed wheel on the axis and for the belt is no possibility to stretch it like you have. What do you think, is that really necessary?
Most interested in this mod. Currently printing parts for your Hanging Z axis. Investigating the dual lead screw. But cannot source the belt or anything like it. On your thingiverse listing give a pitch of 2.54 which doesn’t add up at all. Can find 5mm pitch which at 230 teeth gives a length of 1150mm. But can’t find any stockist of that length. (not even sure how they specify length anyway)
The length you quote of 1168.4mm equates to a pitch of 5.08 (2x2.54) and 230 teeth.
Further thoughts. Does the single Z motor cope ok with running 2 lead screws? Is it worth or necessary to boost the driver - useing DRV8825 for instance? Do I then double figure in the firmware to allow for 1/32 vs 1/16?
If you switch to using a DRV8825 then you would double the Z-axis steps-per-unit value, correct.
I have not made the dual leadscrew modification, but I would be very surprised if the stock motor can’t handle this. I would check the belt alignment and tension to reduce any friction in the mechanism before I tried boosting power to the motor.
I have 3,000 print hours against the ichbinsnur’s dual z drive with no complaints from the stock stepper motor.
I had one issue at the 1,500 hour mark, in that the pulleys lost their grip on the leadscrews, and seized up the z axis. This was during a routine fast travel move to home.
I wound up, after reprinting the pulleys and collars, flooding the interior with CA to add some grip. I haven’t had a problem since.
