Workbee CNC Build

[Ian]

I've wanted a CNC machine for many years, as there are often times that I would like to manufacture something out of Aluminium plate (usually to build another machine or piece of hardware!). Last year I found that there were a few open source CNC router plans (OX, Workbee and a few others) which looked like a great place to start a custom build. I've been working on it so sporadically over the past 6 months, I'm fairly sure I mentioned to @Retired in a PM that I hoped it would be ready by Christmas . It's nearly April, but it's finished .

Last year I bought the plates required to build the Workbee CNC machine (the 6mm black plates appearing on the top half of the build), then sourced a lot of the other components independently as I wanted to customise the build significantly. Normally the Workbee CNC machine would sit on a workbench and use a low powered motion controller + handheld router for a spindle. Instead, I've built an all-in-one unit that will house much more capable electronics, a 1.5kw spindle + VFD, basic CNC control panel and plenty of storage space for cutting stock. Most of the unit above spoil board level is based on the open source Workbee design, anything below is my design. The unit is built primarily with Misumi 2020 Aluminium extrusion, plus 2020 v-slot extrusion for the gantry parts.

For reference, the Workbee was designed by the guys at Oozenest (https://ooznest.co.uk/), who have always been a pleasure to buy parts from. I've also heavily used OpenBuilds parts (https://www.openbuilds.com) for lots of the connectors as it works so well with aluminium extrusion.

Here's a photo from the back of the machine, which shows the power indicators and connections for all of the motors, probes and endstops. The heatshrink on the cables hasn't been set on this photo, as I had just finished the wiring this morning. The two doors open to the electronics bay, which contains the VFD, arduino controllers, Raspberry Pi, PSUs and stepper drivers:

Here's a photo of it from the front, where you can see a very basic control panel - including start/hold/stop buttons, emergency stop and a "spindle enable" switch. The centre panel contains a touch screen which shows cutting progress of the job (and can control more advanced functions), the right panel houses jogging joysticks and some common control buttons. There's also a drawer for collets, cutting bits and accessories hidden under the control panel. Excuse the poor lighting, I hadn't realised how the photo looked until I uploaded it just now!

I'm so glad that this machine is now finished, I just need to order in some aluminium plate so I can get stuck in! I'll likely start playing round with testing feeds+speeds on some wood next week to get the hang of the software and cutting process . I'll post more pics when I have some end results.

 

[Retired]

Hi,

What an outstanding achievement Ian; very well done indeed. Thanks for the plug and yes you did tell me you hoped to have it finished by Christmas but didn't state which Christmas; I've been privileged to follow your work in progress and although it's taken you longer than expected you've not taken any short cuts; the end result is brilliant and something I too would enjoy having a go at if only I had the space.

What are the two black squares in the middle of the top picture; are these cooling fans and if so will they be troubled by dust? I'm also interested in the 1.5kW spindle you've used; I'm completely unfamiliar with these spindles so would very much appreciate more information please; I've often seen these spindles advertised on eBay but never looked into them in any detail; I am however very familiar with VFD's having bought a 2.2KW Huanyang VFD (variable frequency drive) many years ago firstly using the VFD to power a single lathe but about four years ago used this VFD to power both my Lorch Schmidt metal turning lathe and my Graduate wood turning lathe both lathes having identical 1.1KW inverter rated motors; these VFD's will run smaller motors once the parameters are adjusted; this means the 2.2KW VFD will run a 1.1KW motor without any trouble at all once set up; I used switching between lathes allowing one lathe at a time to be run and I also added remote controls for speed/start/stop and reverse; I did however run into serious problems with the remote control cables; this really did baffle me for quite a while until I realized it was "cross talk" between motor power and remote control cables; in the end I used Cat 6 cable for the remote controls and ran the cable away from the motor power cables which cured the problem and both lathes have been fine since. These VFD's are wonderful and cost very little (around £100) for so much technology; these VFD's are difficult for a novice to set up and can be highly dangerous; in use the VFD has another danger in that if the motor being powered by the VFD suffers an overload situation the motor is boosted rather like having a turbo installed the power delivered by the VFD increased up to 50%.

I don't want to steal your thunder Ian because I've very impressed by what you've done and it would take me a lot of time to research the electronics you've successfully built in so top credit to you especially since I know you've had more pressing things to do than get this up and running; it looks very professional too and anyone would think it's a factory built machine; I'd have certainly thought so if I hadn't been following your work in progress which by the way I fully appreciated.

I'll be interested to see what you make once you get used to setting it up and using it in anger; what's the top speed; I think my VFD on 400hz took my motor up to around 12,000 rpm when I experimented when the VFD was first bought.

Better late than never Ian and the end result is a top class machine that you can be proud of; I bet you stand back looking at it now finished and thing to yourself "did I do that"?

Kind regards, Colin.

 

[Ian]

What an outstanding achievement Ian; very well done indeed. Thanks for the plug and yes you did tell me you hoped to have it finished by Christmas but didn't state which Christmas

Thanks Colin, that means a lot! Haha, yes I suppose I didn't specify Christmas 2018 . Target met then!

What are the two black squares in the middle of the top picture; are these cooling fans and if so will they be troubled by dust?

Yep, these are two fan filters housing. Behind the panel there are 2 exhaust fans - the idea being that air is filtered from underneath the machine and expelled by two fans. If it works to plan, the filters will be enough to keep the dust out (and there should be minimal filter entrapment as the intake is from a relatively clean area).

I'm also interested in the 1.5kW spindle you've used; I'm completely unfamiliar with these spindles so would very much appreciate more information please; I've often seen these spindles advertised on eBay but never looked into them in any detail; I am however very familiar with VFD's having bought a 2.2KW Huanyang VFD

I bought one of the same ones you saw on eBay for around £110. I spend a little time looking for one with reasonable specs (still keeping it low cost), as the cheaper £90 ones seem to have higher runout and lower quality bearings. This spindle was not earthed via the 4 pin connector, so I opened it up to fix that. Worth checking if you do end up getting one. I'm also running it via a Huanyang VFD that you recommended a while back - thankfully there was some information provided with the spindle to configure it with this unit (although minimal other specs). They seem to be a popular combo on the internet, so had enough confidence that they work well together with the settings provided.

I did however run into serious problems with the remote control cables; this really did baffle me for quite a while until I realized it was "cross talk" between motor power and remote control cables; in the end I used Cat 6 cable for the remote controls and ran the cable away from the motor power cables which cured the problem and both lathes have been fine since.

Good plan on the CAT6, it's really useful for so many things other than network cable! Although I'm yet to put this through it's paces fully, the control mechanism works ok so far. I've got shielded CY cables for the spindle power, steppers and all control cables - I'm hoping it's enough to isolate things to minimise any interference. The spindle and steppers are going to generate a lot of noise, so I didn't want endstops triggering randomly during jobs.

I'll be interested to see what you make once you get used to setting it up and using it in anger; what's the top speed; I think my VFD on 400hz took my motor up to around 12,000 rpm when I experimented when the VFD was first bought.

I'll keep this thread updated as I make progress (and inevitably learn something that I should have done/missed during the design phase ). Off the top of my head, the spindle maxes out at 24000RPM. The speed and enable pins on the VFD are controlled by the CNC software, which took a bit of work getting calibrated. Now I can set a speed on the touchscreen and the spindle fires up to the desired RPM. If the control board fails, a relay disables the "enable" pin. I also need to toggle a switch to allow it to spin up. It's perhaps a bit overkill, but if I change bits during a job I didn't fancy just relying on software to stop things from moving!

This is all very new to me, so it's fun diving in at the deep end .

 

[Retired]

Hi,

Very well done Ian; I'm all for jumping in at the deep end because it usually is most interesting with greater rewards; lots of people are scared to leave their own comfort zone to try something new and I think they miss out on so much. The only thing I'd caution about is safety especially whilst working on mains power equipment which doesn't take prisoners so a novice really should start on low voltage projects to gain electrical experience first.

These Huanyang VFD's are wonderful bits of kit and even at £110 each are relatively cheap for the technology they contain; I've had my VFD for years and it's so far been faultless but it did take a lot of sussing out in order to set the parameters; the booklet supplied with the VFD assumes some electrical knowledge on behalf of the buyer/operator.

With a top speed of 24,000 rpm you've got a nice cnc router and it should give a very clean cut indeed; you'll be keen to use it in anger.

Kind regards, Colin.

 

[Ian]

I've got the spoilboard nicely levelled and the test cuts in MDF all went really well . Some aluminium arrived yesterday, so I can start testing that out. I want to make an XYZ touch plate from a 100x100x10mm cast aluminium plate, which will be a good test. It'll be an interesting experiment finding out the correct feeds+speeds, but I'll start off slow!

 

[Silentrunning]

Nicely done Ian. What an awesome project.