Novamill on Mach3

flyingmike · Post by **flyingmike** » Mon 18 Jul , 2011 20:52 pm

Hi Guys,
After a few mods I have finally got my Denford Novamill up to the stage of configuring mach3. I have added new stepper motors, Nema 23 double stack motors on the X and Y axis and a Nema 34 single stack motor on the Z axis. The control I am using is from Rhonmac cnc with the controllers set to 8 microsteps.

The machine has the standard belt drive on each axis giving a reduction ratio of 1:2.5 the pitch on the ballscrew is 5mm. From this I worked out the steps per unit should be 800 (for a metric setup) I set this for each axis and when I commanded a movement of 1mm I got a very small movement on the machine. To get the machine moving the same amount as that commanded I had to set the steps per unit to 25889.97.
I`m confused as why my calculated number of 800 is so different to the actual one required?

Also, such a high steps per unit the max speed is reduced to 57.94 which is about right from a crude measurement I did with stopwatch.

One thing to note is I`m only using the demo version of mach3 as I wanted to see if it was all going to work before I bought the license. Would this make a difference?

Any help would be much appreciated, thanks in advance!

Mike

angel-tech · Post by **angel-tech** » Mon 18 Jul , 2011 22:16 pm

Have you got it set up on imperial rather than metric, as that's way out. The standard board/stepper setup is 200 steps per unit in metric.

Post by **Denford Admin** » Tue 19 Jul , 2011 8:45 am

The standard board/stepper setup is 200 steps per unit in metric

I'd agree with that and would expect you to be setting the s/w to either 800 or 1600 steps/mm if you are 8x microstepping.
It sounds like steps are being lost somewhere along the line...

flyingmike · Post by **flyingmike** » Tue 19 Jul , 2011 20:59 pm

Hi, Thankyou for the replies.

The native units is set to mm in the config and the MM`s light is green in the settings page.

I am still using the Demo version of Mach3 though as I wanted to see if everything was going to work before I bought it. Do you think this would make a difference?

I have attached a short video of an axis moving so you can hear the stepper motor incase this gives any ideas.

Thanks

angel-tech · Post by **angel-tech** » Tue 19 Jul , 2011 21:40 pm

replied by email.

flyingmike · Post by **flyingmike** » Wed 20 Jul , 2011 22:42 pm

Solved my problem! I was reading the 0 as off rather than on on the switches on my controller. Silly mistake but all sorted now

angel-tech · Post by **angel-tech** » Fri 22 Jul , 2011 0:28 am

it had to be something odd, as it was so far off.

flyingmike · Post by **flyingmike** » Thu 06 Oct , 2011 22:30 pm

I have had the machine running well for a couple of months now and the results are excellent. I have attached some photos of how I did the conversion.

I took the opportunity of having the machine in bits to add a raising block to the column machined from cast iron (messy stuff!)

The stepper motors were replaced with double stacked nema23 motors on the X and Y and a single stack nema 34 on the Z axis.

I used a complete driver unit sold by Rhonmac CNC, this unit had some issues when it first arrived so enough said there...haha If I did another conversion I have learnt enough to put my only controller together.

flyingmike · Post by **flyingmike** » Thu 06 Oct , 2011 22:37 pm

The assembled machine. I bolted a slighlty larger table to the original. This one is sold by Arc Euro Trade for the X2. Fits well and provides 3 T slots rather than the original 2.

flyingmike · Post by **flyingmike** » Thu 06 Oct , 2011 22:42 pm

Some machined parts

flyingmike · Post by **flyingmike** » Thu 06 Oct , 2011 22:53 pm

In my opinion these denford machines (Novamill, Triac e.t.c) blow away anything currently on the market for the model engineer. Good examples come up from time to time and once converted only cost equivalent money to the new chinese machines and offer far greater stiffness and precision. Maybe a gap in the market here to bring these machines back with new controls.

angel-tech · Post by **angel-tech** » Thu 06 Oct , 2011 22:58 pm

totally agree, i've been saying this for years.

Post by **Denford Admin** » Fri 07 Oct , 2011 8:40 am

Thanks for the compliments - those parts look great !
We are currently offering machine upgrades, but probably still too expensive for the hobbyist
http://www.denford.ltd.uk/index.php?opt ... Itemid=102

flyingmike · Post by **flyingmike** » Fri 07 Oct , 2011 11:29 am

This is good news! does this mean that mechanical spares would be available for the machines? This was always my concern that I would not be able to replace the ballscrew (for example) if I had an accident but the quality of this machine it will probably see me out! haha (and I'm only 31

)

This machine has made my life quite a bit easier for doing my PhD components (in machine tool design).

Out of interest, Why have you decided not to offer the refurb for the Triac? I'm looking at one of these for my next project.

angel-tech · Post by **angel-tech** » Fri 07 Oct , 2011 13:51 pm

how much did you raise the column by ?

flyingmike · Post by **flyingmike** » Sat 08 Oct , 2011 11:50 am

I raised the column up 70mm as this is the distance from the centre of the stepper motor to the mounting holes on the bracket. So by rotating the bracket 180 degrees it looks down (into my new raising block) rather than looking up into the column casting as standard. However, you could make your raising block as large or as little as you like just by making a new bracket to hole the stepper motor and just being carefull to get your belt tension correct. I did need to move the hinge holes on the cabinet as well.

My plan for raising the column was for two reasons, one was the use of the quick change tooling which can eat height quickly and the second was I plan to build a 4th axis for it. I have since found a very nice miniature clarkson tool holder which is very low profile. Similar low profile collet holders are on ebay at the moment.

angel-tech · Post by **angel-tech** » Sat 08 Oct , 2011 13:19 pm

I noticed the 70mm centres on the stepper myself, and it does simplify it a bit.

JohnHaine · Post by **JohnHaine** » Mon 21 Nov , 2011 22:27 pm

Hi Mike, your machine looks good, as do the machined components. Having just bought a Novamill without the electronics one option is to upgrade my lathe CNC drivers to 3 or 4 axes and drive the NM from that (unplug the lathe first of course!), using Mach3 (currently I use Mach3 turn on the lathe). May I ask a couple of questions about your conversion?

Why did you decide to replace the steppers? As far as I can tell the original ones should be compatible with modern drivers as they have separate windings without any commoned connections. I'm hoping to use the originals at least to start.

Also, how did you deal with the spindle drive? I don't know what the motor voltage is, but I do have a 180V DC motor controller so would hope to use that but can't find out what voltage the motor needs, could you help?

I'd be really grateful for any information you could provide.

Thanks, John.

angel-tech · Post by **angel-tech** » Mon 21 Nov , 2011 22:51 pm

the originals steppers will work well, i've converted quite a few Novamills to Mach3.

JohnHaine · Post by **JohnHaine** » Tue 22 Nov , 2011 10:04 am

Great - thanks for the help.

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