Ballscrews might be a good upgrade if not already fitted. For the X (I assume you mean left-right) axis, it looks like the electronics are bolted to the back of the rear rails. Removing that and fitting a piece of 6mm plate right across, bolted into the edges of the side "cheeks" would be a lot more rigid. A Z axis assembly fabricated from alloy plate would be more rigid than plastic if you want to do routing.

Even on a proper mill pure soft aluminium is horrid to machine, much better to use a machinable alloy (6082?). A material which is a delight to machine is Corian, get offcuts from an up-market kitchen fitter. Good for making precise parts that don't need to be very hard or strong. There is a material not unlike MDF called Valchromat which uses a melamine resin rather than urea formaldehyde. It routes very well, doesn't blunt cutters like MDF, is through-coloured, and not nearly so unfriendly to breath the dust. Great for things like spoil boards, small sacrificial mounting plates etc. Expensive to buy an 8×4 sheet so try to get offcuts. I actually got a sun-bleached sheet almost free that had been in a showroom, I also made a clock case from new stuff (blue), I had the components CNC routed and took away all the offcuts too, I seem to have a lifetime supply at least for small projects.

Basically the rpm of a typical DC motor depends on the number of turns, the magnetic circuit design, and the applied voltage. So a motor that runs at 10,000rpm on a 24v supply will very nearly be generating 24v back emf with no load. At 12v the same motor would run at 5,000rpm. Controlling by PWM, you take the "duty cycle" which is the ratio of on time to on+off time and multiply the supply voltage by that fraction to find the effective voltage. So a 24v 10,000rpm motor supplied at 24v with 50% duty cycle will run at 5000rpm.

Link – May be of interest.

Nicely presented, Andy

MichaelG.

On 3 April 2023 at 12:23 IanT Said:

I’ve managed to resist buying one of these cheap ‘engravers’ Russ as I’m not sure of it’s practical value if you are already set up with manual machines (at least for most of what I do).

But then I didn’t originally think I really needed a 3D Printer and I’ve found a lot of uses for that. Learning 3D CAD made a big difference in my case. It wouldn’t be nearly as useful if I was just printing Thingiverse designs…..    So I’ll be interested in hearing how you progress.

Regards,

 

IanT

Was having a look around to see how things were going (e.g working) here now and spotted my earlier post above wrt 3018 CNCs…   🙂

Well, I’ve been looking at a high-spec 3020 CNC router (from Fox Alien) that comes with linear rails and ballscrews as standard. I’ve watched quite a few ‘Upgrade 3018’ videos and also considered a DIY/CNC conversion approach but finally decided that I probably had (for a change) more money than time and needed to spend a bit more than the standard 3018-type router usually costs. A ‘Black Friday’ special brought it just within my ‘top’ price and it was just a bit too tempting to resist. So one of these WM3020s is on it’s way and once I’ve figured our how to make it actually work and I’ve got something useful to show, I’ll report back…

https://www.youtube.com/watch?v=B79OkSwSyxM

Regards,

IanT

PS The site is better than last time I came, not perfect but maybe livable. Hopefully performance will continue to improve…it needs to

They’re a bit weedy for anything serious but the GRBL makes the CAD/CAM part a lot easier to learn and they are fabby CAD learning tools

There’s always something else to learn… ugh

There’s always something else to buy…ugh

If you use a program like candle 1.1.7 you can dig about in the “locked” part of your GRBL settings via the console and sort out your limits for various movements

The initial settings are often very conservative

use $$ to get the data stream which is often a single huge line (yeh great thanks!)

copy paste it to a text file for viewing

https://www.sainsmart.com/blogs/news/grbl-v1-1-quick-reference

That was what looked good to me, many videos I have seen of these small machines just nibble away at aluminium and produce dust, he was making good size chips.

I find my CNC makes far less mess than the manual mills and although I only have a 5000rpm spindle it is also quieter than the X3 as there is no gear noise from the head. As the 30x 18/20 machines are so small it is not a major job to put them in an enclosure if needed.

The machine Ian links to has a 10K spindle which is not too bad, it is the ones with 20K and upwards that can wine combined with the less rigid ones where high pitch chatter becomes a problem but the one in the video does not seem to suffer from that.

What it WILL do well is teach you about CAD/Cam stuff and what’s needed to upgrade a mill or lathe (NEMA 23s etc) for a quieter CNC life

Yup

More money

Which will show you that your conversion machine needs ballscrews once it’s been CHC’d because of the high accuracy achievable

Yup

More money, plus the effort of conversion

The best route with these things may be lasers

Yup

More money

but I doubt lasers last for very long unless you really know how to get the longest most e-f-f-icient use out of them

(sigh)

I’m afraid there’s a limit on how much I’m willing to spend Ady.

I looked at a ‘conversion’ kit and it was all adding up very quickly – NEMA 23s, Controllers, Ballscrews and of course – the time to actually do the work. A few years back, I might have been tempted but I’m beginning to realise how precious time is now. Another factor is the ‘downsizing’ issue, the time when we will have to move and perhaps I can no longer house my larger/heavier machines. I will then have to downsize my ‘engineering’ activities to match I’m afraid. Fortunately, modelling in Gauge 3 provides scope to build nice big models without needing too much room to do so. Maybe a carriage or two?   🙂

Actually, a number of my G3S colleagues have been using CNC for a while now and producing quite outstanding results. Most recently this GWR Armstrong has been completed and it really is quite special!

http://g3forum.org.uk/index.php?PHPSESSID=271fea94b99b7ccf7ec3fe71d5c9928b&topic=3098.msg19602;topicseen#msg19602

I have a feeling that Mike mentioned having access to a Syil CNC. When I checked what a ‘Syil’ was though, it was a little bit more than I could afford, so the WM3020 will have to do!  🙂

Regards,

IanT

Fairly standard practice if you are mounting work where depth needs to be fairly accurate, I often skim the top of a mounting block if held in the vice or a backing board if fixed to the table. When you are setting your machining heights to 0.1mm increments or less then you need the work and what it is fixed to to be flat. particularly if you ar estarting with stock that is already the finished thickness, not such an issue if it is thicker as you just skim the top of the work and often the bottom as a second op.

Good example here where I set the depth of the outer profiling cut to be just a bit more than the material thickness and you can see I have cut through but not gone as far as cutting into the board below. So within two thicknesses of tape.