Hi, been looking to make big sized pen plotter but Im not really in a position to make one and started to look for a ready made and yours have received such good reviews that I’d like to buy one but I think your design could be improved and I wondered if you might be willing to to make the modifications that I think will improve the design and either charge me a reasonable fee if the changes do nothing or normal price if we learn something important?
Firstly let me say there may so many reasons why the changes Im thinking of are useless or worse but Im unaware of them and so please forgive me if the first engineer who understands what Im saying recognises it as tosh.
The main thought is the two current Y axis motors should be attached to the outside of the frame and use a looped timing belt passing thru and looping back the top half of the 2040 with both ends attached to the shuttle.
As it is, the motors are being moved and adding momentum when less momentum is surely better? It doubles cost for the timing belt but saves some money on the wiring and prob more reliable if the wiring is not being flexed.
Do the angles of the belt change as it is now? (which would be altering the tension) or do you have more pulley wheels to keep it flat - adding friction.
If you can imagine in place of your current custom frame that holds the two rails apart the frame also provided a bracket to correctly place and orientate the two Y stepper motors. Their axis parallel to the ground and at the correct height to line up with the 2040 top channels. A driver pulley fixed to the stepper motor and a freewheeling pulley on a tensioner sticking out the other end of the 2040.
As for the linear bearing axis, again a looped belt with a tensioner with the belts anchor on the shuttle and using the upper most side channel of the 2040 so it is near the slider and will produce less unwanted angular tension.
Im fairly sure the changes could be tried out without anything more than a timing belts, a few brackets and some nuts and bolts so if you feel unable to help then I shall buy one of yours and get whatever’s needed to try the changes out myself.
If you feel you may be able to try these changes even as a hack with bolted brackets etc. please get back to me with an idea of the cost.
With best wishes
nick