Hi, I'm looking for some cheap optical incremental encoders. (Cheap is £15-20 - I have heard that you can get them for around $30.) 2000 PPR, able to fit a range of different motors. (Will be using them on the back of stepper motors, both NEMA 23 and NEMA 17.) Metric shaft size. 2 channel quadrature. I'm in the UK so a UK supplier is ideal. Any ideas as to where I could get them from ?by yngndrw - Stepper Motors, Servo Motors, DC Motors
A few people have mentioned about only half the torque being required with this set-up and some have even mentioned about adding gearing to make this a quarter. I'd just like to point out that with stepper motors, their torque rapidly degreases as the speed increases. This belt set-up is effectively a 2:1 gear ratio, so it requires the stepper motors to run at double their normal speed for theby yngndrw - Developers
If people are worries about running the teeth of the belt over the idler, why not use a pulley instead of a smooth idler ? That way the idler's profile would be a perfect match.by yngndrw - Reprappers
Hi Guys, I thought this might be of some use to some people. This eBay seller is selling ball-screws for very cheap - $45 for a 300mm ball-screw with ball-nut and free shipping. They also do end machining for an additional $15. (Either for an existing support such as the BF/BK12 or for a custom design.) They have a range of sizes and thinking about it, it's probably around the same cost as soby yngndrw - General
It looks like you have only connected one pin for each cable, halving the capacity of the connector. You should connect pins 1 and 2 to the first cable and pins 3 and 4 to the second cable.by yngndrw - United Kingdom RepRap User Group
Thanks I'll try that tonight.by yngndrw - 3D Design tools
I'm a little concerned with how good the ground would be between the two power supplies, but I guess for this usage it doesn't really matter. I'd probably have both the heaters controlled by a separate microcontroller so that if the main microcontroller does crash the heater will still maintain its temperature. (With a watchdog)by yngndrw - United Kingdom RepRap User Group
The only problem with bringing the signal out of the main connector is that there is no ground connection to use as a signal reference. Do you think that the PCB heat bed alone (I.e. with my own drive electronics) would be able to take the peak current from 27 / 35V PWM ? It would be a pain to have to use separate power supplies. Thanks for pointing out the MOSFET issue, I'll have a look at theby yngndrw - United Kingdom RepRap User Group
I might end up just pulling out the MOSFETs and replacing them with pin headers so I can have them external (Would allow me to break out both the signal and the ground in a single connector) but I will save that for later - For now I will just use it as-is, but with a 12V supply. I'm going to be pretty frustrated if the board doesn't just work with the PCB heat bed and 12V as that is what it wasby yngndrw - United Kingdom RepRap User Group
Hi, I am trying to make a parametric Globoidal CAM model in OpenSCAD but I've become a little stick on how to make it. My initial idea was to make a profile of the turret (Output wheel), extrude / twist it to make a model which represents the path of the turret, then difference this from a cylinder to make the cam. Attached is what I have so far. () My problem is that there's no way to add a tby yngndrw - 3D Design tools
Thanks, I'd forgotten that it just switches the ground and that I can just use a separate 12V power supply for the heaters, while still maintaining the 27V power supply for the motors. It's a shame that the Sanguinololu board doesn't have separate heater and motor supplies.by yngndrw - United Kingdom RepRap User Group
Hi, I have bought a Sanguinololu and a PCB Heat Bed (MK2) and intended to run it on 27V, but have only just considered the ratings. The Sanguinololu is rated for 35V but everyone who uses the PCB Heat Bed seems to use it at 12V. At 12V (10A) it should dissipate 120W but at 27V (22.5A) it will dissipate 600W ! The hot-end should have the same problem too. Changing the firmware to limit the PWMby yngndrw - United Kingdom RepRap User Group