Let's talk CNC

#1

Hi All

I can’t seem to find any recent threads relating to the potential purchase of a CNC machine for the space, so I thought I would start afresh. All comments welcome! A long post.

I believe that a CNC machine would be useful for most members of the space - with regular cleaning and a detailed set of induction material, a CNC would be useful to all areas of the space, from circuit boards and dense wood to big chunks of metal. With this in mind, I think there are two potential routes to take.

Route 1 - Build It!
This is very much inkeeping with the Makerspace ethos of DIY to the extreme. It’s also the cheapest option, although not necessarily the most accurate method of doing things. Designs are readily available, as are some parts. I’ve listed some pros and cons below.

Pros

  • Cheapest method - a medium sized mill that can do foam accurately (+/- 0.5mm) is under £1000.
  • We can build it ourselves - the joy of making!
  • Custom design means that members will be able to service the machine more readily

Cons

  • Inaccurate - with some very fine tuning, +/- 0.1mm should be OK - anything more accurate might be a little too ambitious!
  • Parts can be a little hard to come by/have long lead times
  • Wood capable machines are more expensive.
  • Light (1mm) Aluminum engraving would be OK - but no cutting. No steel, brass or any other metal.

I have some experience with building a foam-capable CNC at home. It’s certainly doable, but not altogether practical.

Route 2 - Buy It!
I think that purchasing a small/medium sized CNC would work best as a long term investment. Although yes, a new shiny machine always catches the eye, it solves most of the problems in Route 1, but is far, far more expensive.

Pros

  • Wood and Metal (steel) capable
  • Accurate (in my experience) to about +/- 0.025mm
  • Capable of small, repeatable production runs

Cons

  • Damn expensive. A small, high quality CNC mill starts at about £4500, but can easily run to £40k.
  • Heavy.

My vote would be to bite the bullet and get something high quality/mid sized (the Tormach 770 comes to mind. Of the 19 people I know who own one in the US, I have only heard 1 bad thing and that was it was too heavy for my buddy Jerome’s truck).

But - that is only what I’d do. What route would you take? Is there any money set aside for a CNC? Do both of these options suck? I’m more than happy to take the lead on this project for research, getting training and delivering inductions.

  • Rob
#2

Let’s make one.

There was at least one crowd funding project and you can get a cnc head for a 3D printer.

Do Ultimaker have one?

#3

The tormach has been discussed before and I do believe there are funds set aside for a Cnc mill (I maybe wrong)

Search for old threads

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#4

I am aware that there have been discussions in the past at SLMS. I have lead a cnc group in a similar setting in the past with mixed results

Whilst I believe that CNC does add a very nice function/service there are considerable challenges due to a) the nature of the equipment and the maintenance needed and b) the skill level required to operate [it is not trivial] managing peoples expectation around what it can do and the personal investment in what is requires to get it going are not to be underestimated.

I am a a caveated supporter of CNC given the above challenges, I have some of my own CNC kit two Mills (a boxford and bridgeport interact) as well as a orac cnc lathe.

I would suggest the way forward is to arrange a face to face meeting to discus …

#5

The Tormach is a popular machine, one of my mates here has one and a major regret of his is he does not have a tool changer and the last time I spoke to him there was no support in the UK (actually I wondered if there was an opportunity there for me kind of kidding but also not :slight_smile: )

#6

Actually nothing could be further from the truth, from day zero we’ve always bought kit that was designed and preassembled by reputable manufacturers.

The reason is that the kit needs to be a thing to make projects with, not a project it’s self. DIY laser cutters and 3D printers invariably are more fiddly to use and require more work to maintain.

This is why none of the main tools in Makerspace are DIY built. And the exception is the old CNC which is an exemplar of this issue.

That being said I clearly support option 2 but I also think members need to contribute the funds themselves as we cannot afford thousands on a CNC when we need to save for the future of the space.

#7

I’m in talks with a friend to hire/purchase a self built CNC to shapeoko standard (alu profiles, etc) with a bigger working area (about 2m^2). @directors, @metaltechs and community agreeing this could turn into a medium term loan while options are considered?

#8

@unknowndomain in principle I would agree with you regarding professional industrial grade kit however in terms of self build it also depend on the kit and who is building it , I have no prior knowledge of SLMS strategy regarding kit but feel in principle what you say makes sense.

The Tormach is what I would call a pro-am (profesional/ameteur machine) whilst capable it wont be as hardy as a HAAS or similar but I think that even a Tormack would be pushing the SLMS Budget This bit of kit whilst being capable still is not as hardy as a tank and will require gentle care

One of the points I want to stand out in what I am saying is the cost or attributes of the CNC machine is dwarfed by the required skill to maintain it when it is used by a communaly and the training and educational requirement for people to use it competently and safely . Good CAD CAM and Engineering Knowledge are required as well as a careful and patient disposition.

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#9

Hi Im interested in a CNC mill, I would be interested in making some injection moulding plates.

I have CAD knowledge and have designed several injection moulding tools and own three tools personally.

I would totally be up for a machine and to take the time to learn how to use it.

#10

I would be in for the buying one option and one that comes with a good manual.

#11

The machine in the post is around $7,000 USD and $11.800 for the starter pack.

#12

A big router like that and a mill are very different cnc tools - Both would be useful.

We had the offer of a big cnc loan but need to fix snug to fit it in. I would absolutely love to have both but a mill is probably most useful and also smaller.

I have been involved with building a couple of cnc’s and often seems to involve a lot of downtime. I think buying something tormach ish would be good but needs pricing and more investigating. Currently though focusing on getting through the welding before moving on to cnc planning.

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#13

would like to see the lathe up and running before there is talk of a cnc mill, if we cant get people inducted on a tool we have owned for nearly a year, what chance do we have with one we don’t own yet?

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#14

There’s also the very real need to stop buying tools that require more space because we hardly have any storage as it is.

And we need to stop spending money so we can save for the future.

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#15

I’ve got folk inducted in about three months on the mig from first time use to inductions starting.

The lathe - some very talented folk are working on fixing it, i don’t have the experience to do this.

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#16

A visiting engineer, with experience of similar machines, suggested a strip down service. I’d love to be involved if that’s on the cards?

#17

A strip down service 100% needs to happen, as well as the repair of the thread cutting functionality, which is what was causing the severe knocking noise. Here’s a list of what needs to happen to get it operational to a good standard:

  • Replace bushings (part 30759 is the near broken one, but they all need doing)
  • Replace lower screwcutting gearshaft (part number is not in the manual, I’m waiting on Colchester to send me the correct part number)
  • Gear oil replacement
  • Headstock & Tailstock Service
  • Gearbox service
  • Bed cleaning & leveling
  • Address floor fixings

Additional things that probably should happen:

  • Dial servicing
  • Replace chip guard
  • Suds pump service/topping up
  • Change dials to metric
  • Pay someone to do final run out measurements & fine tuning (Transverse, Spindle Centre, Spindle Nose, Cam Action, Spindle Taper, Headstock Alignment (Vertical & Horizontal), Tailstock Spindle and Taper Alignments (Vertical & Horizontal) & Cross slide alignment

None of the final measurements should have a run out of greater than 0.01mm.

I’m happy to address all of this (except final alignments, we should definitely pay someone with 85493 years of experience to do this), but the parts need to be ordered in and it needs basically a week’s worth of evenings to get it up and running to the level where it is once again an accurate machine.

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