How to slow homing speed?

LowRider CNC Troubleshooting
1

Hi, anyway to slow down the homing speed? It seems to hit my endstops too hard and move them slightly. Please help!

2

You would need to modify this line in configuration.h, compile, and then flash your board:

// Homing speeds (mm/min)
#define HOMING_FEEDRATE_MM_M { (30*60), (30*60), (3*60) } // { (50*60), (50*60), (4*60) }

Reduce the two ‘30’ values however much you want. It is currently set at 1800 mm / min in the V1 maintained firmware.

3

Does your machine move the right distance? If you jog 10mm, does it move 10mm or more like 20mm?

The default homing speed is pretty slow, so something seems a little fishy.

4

Yeah I agree. Default speed shouldn’t be moving anything. Are your end stops secure? Ideally you should be able to crash into them and the steppers would skip rather than plow through them.

5

Yes it moves perfectly fine but seems to slam into my endstops, think a very very heavy gantry could be an issue?

6

Unless it is skipping steps, it should not move past where it wants to stop. The steppers are open loop, but very precise, until they skip steps.

  1. If it is moving very fast, then it might not notice that it has hit an endstop until it has moved past the switch. This is a function of the speed, and the amount of latency detecting the switch. Unless you have some filtering electronics on your switch, the latency on your machine and everyone else’s should be about the same. The speed is also the same as everyone else’s. So I don’t see how that could be only affecting your machine.
  2. If it is skipping steps (or maybe if something is loose, like a pulley/grub screw or a belt) then it would try to stop, and go a little further. A heavy gantry could cause that. But you should be able to notice (either the grinding noise from skipping steps, or a lot of slop in the axis). This would be something only your machine would experience.

Are you having any other endstop issues? Like maybe the Y1 and Y2 enstops are swapped? That can cause some funky behavior.

7

I’ve checked the end stops, they correspond correctly on board and motors. The cabling used is shielded. It seems to be weight as there is no noise or grinding. Belts are tightly and grub screws checked too. It seems to be the weight as I think gantry must be 30-40kg in weight. It is on oversized belts and rails.

8

I’m going to re check everything and slow the speed down and see what happens, will get back.

9

I may have overstepped. If you want to change the speed, Robert’s suggestion is the correct one. I am just looking out for deeper issues. This is the first time I’ve heard someone asking for that change in speed. It is always your machine, and you can edit it however you’d like.

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10

I greatly appreciate all the responses from the obvious to the ones that grant deeper knowledge and understanding.
I’m sure before building, just like me, others also read through plenty of your posts to get to grips with this endeavour.

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11

Thank you @Robert, @Jeffe and @brenavich980.

Mine was set at 5060 = 3000. I’ve knocked it down to 3060 = 1800 and now it doesn’t slam into the endstops.

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