Instrument maker

[JAZZCNC]

at least 70kg gantry with all mounted

Too many variables to say that. What size machine.? How deep bowl.? What material.? What cutter size/length.?
Smaller machine well designed can still cut deep bowls with good MRR and doesn't need to be weight of small tank.

3D work by it's nature doesn't have large step over so the cutting forces are low when doing the finishing. The bulk is removed by roughing so finish isn't important only tool life becomes a factor. So again well designed machine can handle this with good tool life but without being massively built.
Mass only really comes into play when cutting deep and requiring respectable finish without using finish pass. For any decent work that requires quality finish then machine weighing 20ton will still need light finish passes, infact several semi finish passes for some work.
The Massive weight is then wasted and infact acts like stone around it's neck. To move this stone is costing money.

So what I'm saying is while Mass is good sometimes it's not always benifical or required for certain types of work. IMO 3D being one of them.
You want fast moving machine that can take light cuts which doesn't require heavy machine and all the extra expense that goes with it.!

Strong doesn't have to mean heavy or like you seem to think and preach must be STEEL.!! Good design and Aluminium will work just as well.

I'll make this point Clear by refereing to 5 Axis JOBS Machine (costing £250,000 20yrs ago) which I nearly bought few years ago which originaly came from Mclaren F1 and used for machining the Steel moulds for there Composite parts. The WHOLE Z Axis which was over 1Mtr long was made from ALUMINIUM.!!!

[Grambot]

So, it seems that building a machine is the way to go here?

I'm wondering what the sort of costs would be for my needs - At least 500mm x 200+mm x 120mm, capable of +-0.1mm on wood and aluminium. And then some sort of enclosure, and dust extraction?

[Clive S]

So, it seems that building a machine is the way to go here?

I'm wondering what the sort of costs would be for my needs - At least 500mm x 200+mm x 120mm, capable of +-0.1mm on wood and aluminium. And then some sort of enclosure, and dust extraction?

Wal built a very nice machine here http://wrbl.tumblr.com/mill-build he is going to upgrade it with linear rails but have a look through his log and you will see the fine detailed work he has done with it.

[Ger21]

Don't forget that when you turn a big block of wood in to a bowl, you'll have about 20x (if not more) the volume you removed in the form of dust and chips.
Routers can make a huge mess, that can be difficult to contain at times.

[JAZZCNC]

So, it seems that building a machine is the way to go here?

I'm wondering what the sort of costs would be for my needs - At least 500mm x 200+mm x 120mm, capable of +-0.1mm on wood and aluminium. And then some sort of enclosure, and dust extraction?

Nearly impossible to answer accurately because don't know your skill level and how well equiped you are.
The cheapist way is to build frame using steel box section but this requires you are equiped with welder etc. Knowing how to weld also helps but believe it or not isn't exactly vital.? if your prepared to have a go then quite easy to learn with just few days practise.

There are some key areas on machine, like Z aixs that are quite difficult to make without some machining work so you will probably have to pay someone to do this if not equiped with machines to help.

Like Gerry says Extraction is Very important on router and even more important if enclosed. You'll need serious vacuum system if enclosing, little Henry type Vac won't cut it if removing large amounts of chips.

For Good machine with reliable quality components (not including Vacuum system) then you realisticly need to budget for Minimum of £2K with £2.5k being probably closer to the mark.
If your well equiped and can use your tools then along with some savy buying you can get this down.

What you MUST NOT do is Rush the build or be tempted to Buy Cheap Electronic kits you see on Ebay Etc. This is sure fire way to waste money and at best end up with under performing machine. Worst case you end up with Night mare basket case of machine which will deflate and turn you off CNC for life.!!
Doens't need to be this way and if you have patience along with the good sense to ask and listen then you'll build machine that will fill you with pride and put huge smile on your face.

Suggest you start looking around the Forum at differant machine style etc and read the Build threads front to back. Then start thread of your own outlining what you have in mind regards style and Components. Then when we will come along rubbish all your suggestions, kick it about bit, flip it, then Bing bang before you know it you'll have Cunning plan and away you go.!

The secret to SUCCESS is NO BUYING, NO RUSHING and most of all NO SHERKIN.? By this I mean do the research, learn whats needed and don't try to take short cuts. Design the machine Make Plan then Start building.

Don't be afraid to ask any question no matter how stupid it may seem. We ALL will have asked it at some time.
No one here will Mock or berate you for Stupid question but we will take the Piss out of you if don't ask it and get it wrong. .

Go for it don't be afraid. BUT be HONEST WITH YOUR SELF, Ask self if sure you have the skills and mind set to do this. . . . If not you will Fail.!

[Grambot]

Routers can make a huge mess, that can be difficult to contain at times

Good point Gerry, so I'd also need an enclosure, for mess and sound

Nearly impossible to answer accurately because don't know your skill level and how well equiped you are

My skill/experience is zero, but I'm a good learner when it comes to making things.

My worry is that a) it may take me too long figuring out how to make a machine when I want to get on with using it, and b) when I do make it, as its my first attempt, I may make mistakes, resulting in loss of accuracy.

I think I'm going to ask someone to make a decent machine for me!

[mekanik]

Hi
There is a wealth of information on the forum in the build logs, and the guys will help out with any problems but in your situation it could be prudent to have one designed and built by one of our forum members (if not snowed under) Just place a request in the FREELANCE JOBS AND REQUESTS section and someone might be a able to help.
Rergards
Mike

[Boyan Silyavski]

My last advice before you jump in ordering a machine is have in mind the following:

That below will be your main tool/s in this kind of job/ there are cheaper variants, dont worry but i am speaking about the size here/





So start backwards from there. What spindle you need for that bit, what speeds the machine to move, how will evacuate the chips produced and so on.

Download HSMAdvisor, It has trial though i greatly advise to buy it, as it starts to become indispensable tool for me and if one knows how to use it it will save a lot of money, even when designing a machine. After my recommendation now there are all the chinese water cooled spindles included there. So choose 2.2 and 3kw spindles there, input the above router bit and start playing around so you see what happens. Change machine max achievable speed and so on.

That's how you will make really educated decision on spindle size, machine max speed, rigidity, motors and so on. Knowing exactly what final purpose is, how good a machine could be and how much will cost you that. Find the acceptable point that all is valid and seems good and that's it.


But i will tell you one thing from recent experience: Its good to have a very capable machine even if you don't know how to use it at first. Cause when you learn, there will be nothing to hold you back. Same with music. Any teacher will tell you to buy the best instrument that you could afford.

[Grambot]

Yes, I agree, I want a machine which would enable me to grow in the future, and experiment with new designs. And I'm impressed by just how strong your machine looks!



You said in the description that it achieves 0.1-0.3mm accuracy - is that good for a DIY machine? I would really need no more than 0.1mm, because the parts I'm making are so small and complex, and often, several parts need to fit together in a moving mechanism. The more accurate they are, the better the finished instrument.

I'll have a look at HSMAdvisor, thanks for the link