CNC Router: Redux

(Drew Spriggs) #1

Sometime last year we tentatively voted through a budget for a sheet router, which was going to be revisited when we had the room and an extended lease.

I’ve been thinking about this for a while, and that style of sheet router has some limitations for us:

  • cost - by the time you include electrical works, shipping, customs duties, GST, transport, etc we’re not getting much change from $15k (I got 3 quotes for our ideal machines, and all were in this ballpark figure). This would wipe out approximately half of our savings, which isn’t ideal when we are still in limbo with our lease.
  • room - there is room in the woodshop for a full sheet CNC router, however there is no way of getting it in there without taking a wall out or adding a roller door, further adding to any costs.
  • users - there are currently only a few people who could use a machine with an ATC/etc, meaning it gets underutilised, or one or two people get a massive workload.
  • unknown quality - we’re still talking about imported Chinesium, with sketchy aftermarket support and probably needing a lot of work to getting it up and running.

I know of a guy from the GC who owns Sharp Software, and they sell a half sheet router kit for approximately $3k to our door with everything you need to run including a 1.5kw spindle and VFD. Now, this is definitely not the ‘ideal’ kit for us (steppers instead of servos, speed limited due to frame stiffness/spindle power, would need a table/spoil board built for it, no dust extractor), but it does have a few big benefits:

  • it’s approximately 1/5 the cost of the other options we were looking at
  • it’s simple enough with a big enough community of users that there are a large number of members who could successfully use it now
  • it’s from an Australian company, with a legit warranty, and who carry spares/consumables
  • it can be plumbed into our current dust extractor easily
  • it can be moved into the wood shop, installed onto a table and be up and running in a day
  • the owner of the company is a maker, and is super keen to help our communities like ours

My current thoughts are to get this kit as it wouldn’t significantly impact our finances, and to help show:

  • somebody will take charge of it
  • we can run workshops with it
  • there are a number of people who will learn how to use it
  • we really need servos/ball screws/racks for our applications
  • we can justify giving up 15sqm for a limited use tool

David has also mentioned they have a new kit coming out within the next year which has all of the nice stuff we were looking at, and it is within our already voted on budget. If this is the case, the half sheet kit can reasonably easily and inexpensively be retrofitted with a plasma cutter head, and we’d have a half-sheet CNC plasma (a VERY useful tool for us to have).

If all of the above things are true, then in that time frame when we come to upgrade it would have already paid for itself and we’re no worse off financially than we are now - only we’ve got a community of users, we’ve gotten rid of a bunch of our speakers, and we can be known for having a CNC router available for members (a massive drawcard for membership).

I know people are going to be against the idea as it’s not -their- idea of what we should spend money on, but I really think it’s the most logical step for us to move towards having a industrial-quality full sheet router in the future.

(Ryan Marple) #2

Definitely seems like a smaller unit would be a better way to get started. It would also be a proof of concept of whether a larger unit would actually be utilised down the line. And of course, lower cost doesn’t mean lower quality, especially in CNC. You can just look at the history of 3D printers to see that…

(Andrewm) #3

I would imagine 95% of your use case to attract new people would be mame cabinets.

That needs an 1800 long piece for the side. Is a 1/2 sheet size still useful for that?

(Ryan Marple) #4

While this may be the case (I’m not sure of the statistics at all on this), what would be the benefit of spending >15k on a single machine which occupies a lot of space and has a high knowledge barrier compared a smaller machine and working out a good process for inducting and training new users. If it proven to be viable in the space an upgrade could be done. In addition, the smaller machine could be used for training purposes and smaller jobs to extend the life of the larger one.

(Drew Spriggs) #5

Although I am sure I haven’t talked to everybody, I can’t remember any members at the Space or inquiries from potential members wanting to build something that would require more working area than half sheet for any reason other than convenience (including me - I’ve had a job done with quarter sheets that could have much more easily be done on a full sheet router, but it didn’t prevent me from getting it done)

(Andrewm) #6

I wasn’t saying that you needed to buy a large machine. I was asking “Is the 1/2 sheet machine still useful for mame cabinets” That is why there was a question mark at the end of the sentence.

As in - can you have the end of a full sheet sticking out and do the cut in two passes?

If that 1/2 sheet machine isn’t capable of that, are there others 1/2 sheet machines that are?

Two question marks here but logic dictates the 2nd does not need to be answered if the first is an affirmative. Maybe again no one will answer and just repeat their previous assertions that I was not arguing with.

(Ryan Marple) #7

Sorry Andrew, I misunderstood the question. Maybe Drew could provide better insight but to me, it looks like nothing can extend from the bed of the machine as it is surrounded by the frame. There is a video on their youtube channel for the device here: https://www.youtube.com/watch?v=zOAdgscC-j4. I think most professional routers do have the ability to extend beyond, however.

(Ian Redmond) #8

Looks like one could have a larger (6’ for an arcade cabinet) piece overhang in the x axis, do the ‘top’ cut, shift down, do the ‘bottom’ cut. Or cut a two piece template, assemble, and hand route a full side. Or make the sides in two pieces - you might be sticking a big ass decal on the side anyhow. The real benefit of CNC in this case is cutting the control surface. I think a smaller router makes a lot of sense for the all of the reasons originally mentioned. The ability to work on longer boards is a good point, though.

(Andrewm) #9

OK - if you can do that then you can surely get a lot of people in Brisbane to sign up for one month to get a MAME cabinet cut. The task then is to convince those people that staying a member is a good proposition.

BTW - does @nogthree have anything to say about a router using plastic wheels on ally profile frame. I think he has some experience in keeping something like that up and running in a semi commercial environ. Do the wheels cope with dust. Is it a good idea long term. Was all the problem with the small one you ran just because other things were poor quality?

(Svenska) #10

So, as being one of maybe 3 people that have build and run these sort of machines I think I should chip in here.
This is gonna be a bit of a longer one. If you want a tl’dr it will be on the bottom.

Yep, that is the price you pay for a piece of equipment that is suitable for our needs. That is already very cheap.

The machine can go into the metalshop until its able to move into the woodshop.

ATC/ets makes a machine like that easier to use and more accessible. Claiming the opposite comes from a position of not enough domain knowledge.

No, just no. The vendor I choose has proven track record.

So, lets judge that machine that is proposed. I think the fairest way to do so is to use the last few projects I cut for members.

We have a part for a Supernova trophy, I did that with @wixted Hedesigned it and I cut it. The part was made from Iron Bark, double sided machining.
Its 42mm high. According to the webpage machine has a Z-travel of:

Max Cutting Depth = Z travel – Material Thickness

For instance a setup with a 12mm spoiler board, the max Z travel is 54mm, so when cutting into a material 30mm thick the max cutting depth would be:

Max Cutting Depth = 54 – 30 = 24mm

That means for our example part a no go once you factor in the tool stick out and realizing that we need to cut 40mm deep. It just does not have the capacity in Z.

Next a guitar body for @gabriel_camp. The body is 38mm thick. Considering the Z travel we might just get away with that. We need to hog out a lot of material, lets grab a 12mm endmill. After a quick look at some cutting parameters, we need 1.3kw to push that tool. With a 1.5Kw spindle that is not possible. Go to a smaller tool? Well, needed pocket depth dictate a high tool stick out and with that massive deflection, awful finishes… You won’t get what you expect from the machine in that case. If you are experienced in CNC you will but the idea is to have it accessible to beginners.

Next some carbon parts for @Drew_Spriggs 4mm thick, some contours and boring. Yep, very much possible on that machine.

Next aluminium brackets for @Drew_Spriggs again. Material needed to be reduced in thickness heavily, that needs torque in the spindle and stiffness in the machine. The proposed machine does not have either. Once we consider the chamfer cut it becomes apparent that it won’t produce a satisfactory outcome.

Quick thoughts on other ideas that I was asked about:

@DistractionKitten wanted sheet steel cut, not possible on that.
Craftpunk wants fullsize people from foam, not enough Z travel
I made parts for the new laser tube, not enough Z travel.
Woodshop people asked about planning raw timber, sawmill style, not enough Z travel and power

I typed enough now. I leave you with a quick bit of thinking for yourself.
Consider the MAME cabinet, figure out the length of the path needed to cut that. Consider a 6mm endmill and a depth of cut of 1/2 diameter. Now tell me how long it will be in pure cutting time to produce all the parts needed for a full cabinet.

tl’dr for the lazy ones:

The proposed machine lacks severely in stiffness, spindle power and linear motion power, that makes it very hard to work for a beginner as you’re always at the limit of its capabilities. Combine that with the low Z travel it becomes unusable for our needs.

Edit:
For the ones that remember, this would be the equivalent of our first lathe.

Please tell me the projects you would like to cut on that CNC and I will tell you if it is possible or not.

(Ryan Marple) #11

Great points; buy once, cry once. I’m definitely onboard with a machine that will just work. I think the main issues will be accessibility and training which will require classes and good documentation. The only benefit I see of a cheaper machine is it can be used to ‘test the waters’ of running one successfully in the space and potentially help set up the processes. But like you said, this is probably negated by the lack of jobs it could handle and the fine tuning it needs. The better machine is probably the way to go in this case as long as there will be proper support for it.

(Svenska) #12

If you want a machine to test the waters, I believe @nogthree has a X carve floating about that is unused?
There is the CNC I build ages ago in Craftpunk as well. It runs GRBL, no one used it since Gandalf died.
There is X craves on Gumtree for sale in the 200-500$ range all the time. Use that to test the waters instead of spending that much on it.

(Ryan Marple) #13

I honestly haven’t done research into potential solutions for CNC routers and wasn’t exactly agreeing with Drew’s solution. Just providing a bit of an analysis on the logistics, mostly with anecdotal evidence. As far as I’ve seen, there hasn’t been a proven method for similar machines to work in the space. While the barrier being hit may be the quality/functionality of the machine, there’s possibly a bit more to it. I’m not sure if this gets done already but creating an implementation plan before purchase would go a long way (full cost of buying and installation, who will write documentation, timelines of when this should be done, how will members gain access, etc). This is of course extra work but it’s stuff that would need to be done eventually and doing it beforehand would probably speed up the process and consolidate resources for anyone managing the space in the future.

(Brendan Halliday) #14

Sorry, I gave the shapeoko frame away a while ago.

I’ve largely stayed out of this thread because I’d like to see this nutted out by keen members and I haven’t been involved in maintaining or building CNC machines for a few years now :slight_smile:

(Drew Spriggs) #15

The CNC in Craftpunk also uses a Dremel IIRC so isn’t really good for anything more than cutting a circuit board or two, which I believe @jabelone tried and didn’t have success with.

The fact still stands there is currently only ONE person at the Space who can run a machine like the Chinese ones we were looking at (which, again, are what I think we should be aiming to get long term) - you. If you’re not there teaching people to use it, who is? Who is taking charge of a $15k machine that nobody else knows how to run or use? It will end up like the large lathe we had, or the plastic injection molder(s), or Hulk - amazing tools which sat underutilised or unused because there was nobody who had the time or the required knowledge to use them.

There are a number of people who could probably figure it out as they go with varying degrees of success, but it would be mostly trial and error. What’s better to do trial and error on - a machine worth a couple of thousand dollars with easy and cheap spares, or spending over half of our savings?

You’re right - many of the jobs you’ve done on the CNC we had couldn’t be done in their current form with a kit like I posted about. NONE of those jobs can currently be done now. Many of those can be redesigned around the limitations of a (again, temporary) CNC router except for steel steel, which could be done with a combination of laser cutting and our manual mill.

MAME cabinets could be done, they would just be time consuming.

The biggest reason we have to get a CNC router and start using it right now is to build cabinets for the tens of thousands of dollars worth of speakers we have now which are still just rotting away on the mezzanine in the wood shop. The router I posted about can do this, and will mean we also don’t have to transport multiple ute loads of equipment when we have to move.

I’ve been pushing to get a CNC router for more than 3 years. There have always been obstacles - people not having enough time to finish off the sign writing CNC we had. Not having the room to put it. Not being able to move a machine like that into a place because of doorways being too small. Not having anybody with the time to take charge of something so complicated. Not having a set lease for a long enough period of time so we’re not spending hundreds of dollars to move something twice.

None of these obstacles to having a full size ‘commercial’ router are going away any time soon.

This allows us to get around a few of them, and when the time comes to upgrade to a full size router we can repurpose this as a plasma/etc as it’s modular - something much more difficult on the cheaper import machines.

FWIW, these are carvings which were done on the exact router I am talking about by somebody who has owned it for only a few months, and taught himself to use it from scratch.

If they can do this with no prior knowledge on this machine, we can do better than this.

(Andrewm) #16

http://www.aliexpress.com/item/32905948862.html

(Drew Spriggs) #17

Not against it by any means, but by the time you factor in shipping, GST, etc it’s only a few hundred dollars cheaper - and that is assuming we don’t get looked after by the company which is keen to partner with Makerspaces and is local to us.

(Andrewm) #18

yeah - not suggesting one way or the other - just pointing a similar options.

There is also this on Marketplace that has round rails on Y and square ones on X instead of v-slot.

But again I am not suggesting one is better than another - just pointing other similar things I have seen out.

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(Jaimyn Mayer) #19

The CNC in craftpunk is very slow and not super powerful as it uses a dremel. It’s ok for very soft material and if you have time to spare. It’s also got a very small cut area and the experience in trying to get something usable out of it is quite frustrating (due to the software). A few small cuts into some aluminium extrusion took a good half hour. It’s a good machine for basic prototypes but I’ve found the effort to get it working is probably better spent redesigning something that could be 3D printed or laser cut.

(Buzz) #20

Drew made an assertion that I feel is wildly incorrect. He asserted there is only ONE person with CNC skills at hsbne… which is nonsense. There are plenty of us that do CNC competently when the need arises on other sorts of machines. Jaimyn has used the dremel thing, as have others. I have used a friends 1/2 sheet commercial router many times (some of u may know Seppo and his router at RFDesign) , and I also own a scratch built Shapeoko2 cnc that i conveniently CNCd many parts of on Seppos router , and it’s used on occasion at my place for routing dremmel-scale parts.
I’m sure there are others at HSBNE too… but most of us are staying quiet… I know I don’t have the desire to run cnc classes, due to other priorities, but it doesn’t mean we have a skills vacuum.

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