Is it best to buy M/C or sub out?

I'm beginning to get more and more interested in CNC machining of metals and wondered if anyone has opinions as to buying a low cost machine or using Fusion 360 to produce the CNC program and then sending it to a company with the equipment to produce the item.

Brian

Edited By Brian H on 17/10/2021 11:59:23

The costs for a single part being made by a sub-contractor will be very high as the set-up for the part may involve pre-production costs that will be added to the part. If you wanted a thousand then that cost will be spread over the thousand parts so would not be too bad. If you think of ten hours of work at £50 pounds an hour as reasonable pre-production work for each item you will see that it soon makes sense to buy the equipment yourself and do it all in your own time. If you think these figures are unreasonable I worked in a department that was costed at £50/hour when I left and I was involved in pre-production work which often involved buying tooling or designing tooling to actually be able to make the required parts. The line "Yes we can bend that pipe for you but we will need to buy some tooling for £2000 first" was often met with "What can you do with the tooling you already have?"

Martin C

Brian

I am almost in the same position as you. I am now using Fusion 360 as a design tool but will be getting parts like engine frame plates cut commercially.

If you want to build models, sub-contract "difficult" items. However if you want to understand and use CNC machines, go in that direction.

After all it is a hobby and most people will not criticise your choice.

JA

Edited By JA on 17/10/2021 12:21:04

Brian H, if you have an interest in cutting metal I would say buy a M/C & do it yourself or if you are more 'hands off' & don't like getting dirty sub the work out, neither route will be cheap but having your own CNC will be much more fun!

Tony

You don't want to use F360 to "produce the CNC Program". Use it to design the 3D part and then that can be sent out if you want to go down that route. The company will then work out the best machining options to suit their machines and tooling and from that use a post processor to get it into a form that their specific machine can use.

There are some online companies that you can e-mail your file to and they will come back with a price, no harm in trying one to see what the cost would be.

Possible reasons for outsourcing:

• To save time - it can be made faster than at home and you have more important things to do
• When there isn't another way of making it, for example requiring a machine or process you don't have
• To get precise or interchangeable parts
• To save money.

Of these only saving time and money need thought. There's no point in buying an expensive CNC set-up and only using it once to save a few hours work. If a CNC machine is to be bought to save time, there should be plan to use it several more times in future, otherwise the one-off is an expensive luxury.

If bought to save money a rather careful comparison is needed to show the purchase really is cheaper than any of the other production processes available. Much depends on volume. For example if I needed to replicate just one old cabinet hinge of the pretty type, I'd mill and hand-finish it, happily spending a few hours doing it. If several were needed, CNC becomes a better option: making one is an interesting challenge, making ten is a chore. And when thousands are needed, stamping or casting are much cheaper than machining once the set-up costs are amortized.

The most likely reason I'd get a CNC mill is curves. At the moment, my interests call mostly for straight cuts easily done on a manual mill. But if I got into ornamental curves or cams, I'd think seriously about CNC because all 3-axes can move at the same time, woof, woof!

There may be a personal motive that overrides production logic: I'm quite interested in CNC and would get a lot of fun out of owning a CNC Mill! I don't mind paying for my hobbies, so it might happen! Boys toys are worth every penny. Do I really need an expensive shortwave radio transceiver allowing signal reports to be exchanged worldwide when the 11 year sunspot cycle is favorable? Do you really need a Harley Davidson, or a Jig Borer, or an IMLEC winning locomotive? Yes.

Does Brian need a CNC machine? Of course he does, and he should order one today! It's a no-brainer.

Dave

As all Brian needs to do is to produce a drawing for his component he is not tied to using Fusion 360. Any cad programme preferably 3D should do the job and leave it to the sub contractor to do the Cam side of things. Most loco builders are happy to have frames etc water or laser cut so why not sub out machining. The only problem is finding a friendly company that is happy to do very small runs, there is no money in it.