DIY Arduino Automated Metal Bending Machine -- Episode 458

I quite liked this project of yours, quite a nice idea, but if I built it, I would make it larger and have a lot of the 3d parts replaced with CNC aluminium or steel parts as it would be of more use to me as a proper metal bender with steel or aluminium bending teeth.

In regards to the gearbox you choose to base yours on, here is a compact gearbox that I designed that takes up about the same amount of room, but has twice the output torque https://www.thingiverse.com/thing:4431811 only downside is the backlash on the gearbox does introduce a bit of error, I have not bothered to fix the backlash error as I only use the gearbox in one direction but more than happy to share the fusion 360 file with you privately, as I have a policy of not publishing my 3d design source file until it has been on thingiverse for 12 months.

thanks, Paul, If I had the means ,time and budget of course I'd like to have it machined in metal, but I also need t ofocus on the electronics aspect as that is the heart of the show.
Mybe I build a beefy version if I get my hands o nthe needed tools budget and time for it.

thanks for sharign the design. Backlash is a major issue for load sensing as it introduces a big error, I played around with even more gearing but the version shown in the video was the only one that still reliably triggers correctly, but is still a lot more lickely to false trigger compared to direct drive.

I must admit using the Trinamic drivers for load sensing is a good idea but if your needing to use a gearbox to increase the holding torque of the motors you are better off implementing a load cell instead of end stops or load sensing, as the main need is holding torque when bending metal, and a load cell will provide more positive accurate feedback of the holding torque.

good points, While that is a good idea I must admit that my main reason to try using the loadmeasuring capabilities of the tmc driver was to learn how to use them.

So for sure there are better ways to get to a resistive load measuring, but also the simplicity in parts needs to be considered, and I thought its quite elegant to not have to carry a sensor on the gantry, as the point of measurment varies with different amterials, some of them to tiny to engage with a side or front mounted sensor.

good points, While that is a good idea I must admit that my main reason to try using the loadmeasuring capabilities of the tmc driver was to learn how to use them.

So for sure there are better ways to get to a resistive load measuring, but also the simplicity in parts needs to be considered, and I thought its quite elegant to not have to carry a sensor on the gantry, as the point of measurment varies with different amterials, some of them to tiny to engage with a side or front mounted sensor.

Its good to learn how to use them as that knowledge would come in handy later on.  But when I am referring to a load cell, I'm considering you could use a piezo based load sensor that is built in to the bending mechanism it self, similar to the precision piezo sensor used in 3d printers to utilise the nozzle as the actual probe.

Using a piezo electric sensor is also more accurate in reading the amount of torque applied, but on the flip side is much harder to implement.

I'm a bit worried that thepiezo might get damaged from the forces aplied to it. I worked with piezos before to build pickups for acoustic guitars and they were pretty fragile.

Yes some piezos are fragile but piezo based measuring devices encompass a large range of measuring items here is the link of a load cell you could look at utilising which provides according to the data sheet provides approximately 45kg of force measure.

https://au.element14.com/te-connectivity/fx1901-0001-0100-l/compression-load-cell-20mv-v-45/dp/3397811?st=load%20cell you would design this into the actual clamp to measure the force applied to the clamp.

I hope this helps

Regards

Paul

thanks for sharing .  Looks like I could incorporate it into the stock holder, but for actual bending I need a different solution as the forces will have to go up to several hundred kilos.

There are other load cells available with much higher load sensing ratings, just do a search for load cells on the element14 site, and refine search by the load rating, to find the load cell that fits your requirements, pretty simple if you know where to look.

Connection of a load cell is much like the connection of a PT100 thermistor, similar connection methods plus you need an ADC pin.

Glad to pass on this information, once you learn how to utilise load cells you'd be surprised how useful they are in these kinds of applications.