New Mill losing steps

[JAZZCNC]

With encoders you get feedback so things like missing steps should not happen.

Encoders won't stop missed steps with Mach3 it's an open loop system and doesn't correct position from encoder feedback. You can connect encoders to Mach3 but they will only display position in Encoder DRO's which you can compare with Mach's actual DRO's but Mach can't do anything about any error.!

Clive is correct you haven't answered all the questions fully and more detailed information, or better still a Video of what exactly is happening will help greatly towards sorting this out.

To be fair it's not rocket science setting the machine up but first you need to establish if there is any mechanical issues. Tight ways, binding screws etc.

Next check all wiring for loose connections or bad wires. It's common for a loose wire at the drives to cause intermitant errors like missed steps.
Like Clive mentioned Noise can be an issue if just occasional errors so check grounding and make sure all signal and Motor wires are shielded with just the control box end going ground.
Check drive settings are all correct. Also check Motor phase wiring is correct.? The motor coils have + & - and so do the drive motor outputs so try to make sure they match up. Things will work ok if other way around but with some drives and controls then it can lead to missed steps on directional changes if the Step pulse edge is on wrong side.

This brings me to the parallel port and BIG possibilty what is your problem.? Laptops and Modern PC's often have 3V parallel ports and this causes problems with missed steps due to not enough difference between Logic voltage.
In an nut shell the way it works is 0V = off(low) and 5v=ON(high) now there's a tolerence in the logic to account for noise etc so 0-2V will work for OFF and say 3-5v for ON (these are rough figures and the drives have the final say.!) So as you can see with only 3V to play with there's not enough room for error as 0v is still off and 3V is ON. So any noise on signal lines can easily trick the drives into thinking these where High or Low signals so either stepping more steps or going on wrong direction.? It's a lottery really with noise and the odds stacked even more with only 3V.!

Laptops also have aggresive energy management often built into the bios so will shut down things like the parallel port and CPU usage when not being used. Now due to how Mach3 parallel port driver works Windows doesn't even know it's there so will attempt to do this.! Even after turning off windows energy saving options If the energy management takes place in the bios which often does with laptops then this can't be stopped.
Mach or should say mach parallel port driver is very sensitive to pulse changes at the best of times and can easily drop or loose pulses if things are not perfect or pushed too hard, so with a poor parallel port or Laptop in particular then chances of errors are hugely increased.! . . . . .. This is why I won't use the parallel port and only use external motion control cards.! (life too short for chasing ghost's.!)

Your BOB may pull the signals upto 5V I'm not sure but it won't and can't account for the Laptop energy management and this is why they are NOT supported by Artsoft. In 99.9% cases Laptops can only be used reliably with a external motion control card.

SO DUMP the laptop.
Check the mechanicals.
Check the Electrical.
Check the drive settings.
The rest is just case of setting Mach3 correctly which we have shown you how or can expalin how and if the above are correct the machine will work.

I will PM you my phone number as it's often easier to help or expalin on the phone.

[EddyCurrent]

Encoders won't stop missed steps with Mach3 it's an open loop system and doesn't correct position from encoder feedback. You can connect encoders to Mach3 but they will only display position in Encoder DRO's which you can compare with Mach's actual DRO's but Mach can't do anything about any error.!

I didn't expect it to it should be a function of the motor driver.

[JAZZCNC]

I didn't expect it to it should be a function of the motor driver.

Calm down Dear wasn't having a go was explaining for OP benifit that encoder won't make a jot of difference.! . . . BUT . . . To respond this one then NO a true closed loop Controller would handle the positional error and talk to the drives regarding correction. The Analog Csmio controller takes encoder feedback and talks directly to the drive but still not true closed loop as it can only fault on error but not correct any error.