Problem Rack Pinion no works

[harryn]

Hi, I am not an expert at all on steppers, but my understanding is as follows. There are two main catagories of stepper motor drivers:
- pulse modulation
- linear

Linear driving was the more popular in the past, and was designed to work with high inductance motors. The main advantages are:
- The relatively lower drive current to torque ratio, due to the high motor inductance (the 22 uH spec)
- Low voltage operation
- Relatively simple drive design using linear components

The downsides are:
- The inability to have high switching speeds
- lack of and extreme micro stepping control.
- Higher motor mass and costs, due to the cost of the high inductance (coils) in the motor

Pulse modulation is more "modern", with the advantages of:
- Cheaper motors, due to low inductance
- Relatively simple design (conceptually) due simple switching transistor components, but more complex software
- High frequency switching is possible

Disadvantages
- Requires relatively high voltage to make up for the short pulse durations
- Requires low inductance motors

What you appear to have, are very expensive, high inductance motors, optimized for linear driving, coupled with a driver designed for high frequency pulse type driving. The drivers are trying to rapidly change the current in a large inductor, which is nearly impossible, except under very high voltage conditions. Eventually, they will burn out those motors, if I understand things correctly.

I would like to suggest that you consider to change your drivers to a linear type, such as a "linistepper". This driver is 1.8 A as standard, and can be improved up to the 3A you need. Most likely, it will only need a 12 V DC supply to run it. There are a number of people using them, and they are very inexpensive. Just search on " linistepper " and you will find the info. There is a guy on the forum here that sells a simple kit for it. I have them, and they are easy to solder up.

Good luck,

Harry

[forumcnc]

dear friend

24/80 volts before my driver I was supplied with the kit also a power supply by 24 times too low for the motors nema 34 12 nm. Now I have fed a current of 70 I've set the stepper to 3200. Now if you try to stop the bridge carries with him

[forumcnc]

Hello

I finished my router with rach and pinion 1.5 module pinion Z20

after I have done a test I noticed this problem when working across the whole rolling out lienee

I can lend a hand to understand how to solve this problem.

Thanks

[ger21]

It looks like you need a gear reduction to gain more resolution

[forumcnc]

In addition to changing the pinion and put smaller and even better to reduce the modile 1.5 to 1?

What do you think

[harryn]

Hi, I am not sure if anyone ever answered your question, but now a year later I understand the challenge you are having more.

I am really happy that you have built such a unit, as it is not so different than what I have in mind.

I suspect that the notching problem in those cuts is due to the stepper taking a step - very hard, and then making this sort of jagged edge cut.

Did you have any luck to use micro stepping in your router ? For instance, 10 micro steps per motor step, so it gives 10 x 200 = 2 000 micro steps.

The resolution increase that Gerry was suggesting was not to reduce the rack pitch, but rather to use gear reduction.

Thanks

Harry