Another 'My First (V)MC' Thread...

[Tam.]

Hi all,

So I'm wanting to get into CNC machining. I've been around machines most of my life (had a hobby lathe in my bedroom from the age of 10...) but never run a CNC machine. Anyhow, the itch is getting stronger so I'd like to pick your collective brains on just how daft my ideas are, amongst other things...

I'm located in the UK, so it seems like a lot of the threads about guidance on getting a machine that I've read here don't quite add up for me (prices, sources, common machines & controls, etc).

My budget is essentially 'as little as possible', but I don't want to waste my time and/or money buying something that will be constant hassle. I've spent enough of my life swearing at terrible quality and laughably under-powered machines already. I'm starting from zero in terms of workshop setup, though I do currently have access to a handful of manual machines in my current job, so I basically need the lot. I can figure out compressor etc etc etc - my main knowledge/experience void is the machining centre itself, and assosciated tooling.

I should mention at this point that another pipe-dream for me is to make some rather large aluminium components, up to almost 1000mm long x 500mm wide (x <100mm thick). These would be heavily machined, starting with a full billet and ending up with only 1 - 2kg. My other plans involve some fairly general job shop work, possibly including some tooling/fixture parts which might need to be decently accurate. Most of the time I'd be machining aluminium or mild or 303-ish stainless, and I wouldn't be expecting to hold microns from the start.

I'd like to be able to program manually for simple parts, but I'll definitely need to use CAM for complex parts, so a control capable of both (even if I need to drip-feed code) is needed.

Of course I'm looking at used machines, since my budget for the machine itself really maxxes out at £15k inc. taxes (£10k or less would be much easier). I've been looking around eBay (not much on offer in the UK nowadays seemingly?), and a bunch of asset disposal/auction websites. I've come across a few mid-late 90's Haas VF0 - VF2 machines, as well as a few Hurco BMC's of similar vintage. There's currently a 2000 Mazak VTC-200B up for auction within budget, which I think could be an amazing machine to own. I've also spotted a slightly suspect 2007 Haas VF4 up for auction. My thoughts on them are as follows:

Haas VF0 - VF2 machines:
Pros:
- Cheap and plentiful
- Plenty of support/guidance online
- Intuitive control
Cons:
- Potentially not much life left in a 20 year old machine
- Not '20hp'
- Too small to make my large components

Hurco BMC30 etc:
- Decent price, not rare
- Apparently excellent control (I haven't researched it much yet though)
- Generally decent machine, more rigid and durable than a similar Haas
Cons:
- Too small to make my large components

This one Mazak VTC-200B that I can potentially afford:
Pros:
- Mazak quality/power/longevity
- Big enough for my large project
- Good control when you understand it? (Mazatrol 640M)
Cons:
- More expensive repairs than the above
- Less support/guidance due to being less common than the above

Suspect 2007 Haas VF4 that I can potentially afford:
Pros:
- Plentiful
- Plenty support etc
- Simple Haas control
- Large enough for my large project
Cons:
- Part of the Z way cover missing
- Looks like it may have had a hard life in the photos

What are your thoughts on these machines, at a glance, please? Any that I should outright avoid for reasons I'm not aware of yet? And do you have any other recommendations or even sources for used machines?

I suppose I'd be wise to only go for the cheapest functional machine really, since I have a lot of other risks and unknowns (and £10k is a years wages for me )...so I suppose that's the smaller Haas offerings, or Hurco equivalent.

I've also thought about older machines like the Mori MV-JR, but can't find any up for grabs right now on the island.

Assuming I do pick up a machine with a CAT/BT 40 spindle, how much should I budget to get set up with a small collection of essential holders and cutters to get me going? And should I try and pick up a tool setter from the start?

Sorry for the excessively rambling post. I'm sure I'll have plenty more questions to follow too.

Thanks in advance for your time, experiences and opinions

Tam

 

[TonyStark]

I can't comment on pricing in the U.K., but there are a lot of things to consider with VMC's. Have you priced the infrastructure stuff you will need like power? Not sure how readily available 3 phase is in the building you ar in but you would need a phase converter to generate 3 ph. Tooling can range widely- but a dozen toolholders, collets, and misc basic endmills would cost $2k plus from an inexpensive but reputable place like maritool, less for some cheap imported Chinese stuff. Vises / fixturing can add up also - a few cheap 6" vises would easily be $1k- better stuff can cost $1-2k each.

The part you mention machining sounds like your biggest hurdle- you are talking about a 150kg piece of billet that you want to remove 99% of the material from? And you want to program it manually? My advice on that end would be to start tinkering around with some demo CAM software and see how long the part you want to cut would take to machine- for those types of machines it could take days!

The machine is only one piece of the puzzle- all of the surrounding stuff like infrastructure, tooling and CAM are just as critical.

 

[706jim]

Haas VF0 - VF2 machines:
Pros:
- Cheap and plentiful
- Plenty of support/guidance online
- Intuitive control
Cons:
- Potentially not much life left in a 20 year old machine
- Not '20hp'
- Too small to make my large components

Yup definitely not "20hp". Kind of like the 7 hp shop vacs that you plug into a 15 amp 120 volt circuit.

I wouldn't go any smaller than the VF2 if you end up with a Haas mill.

Regardless of how much hp is actually output I don't think there is a geared transmission so low speed cutting will be done with dismal torque just when you need it the most.

 

[precisionmetal]

Interesting questions and post. A few comments and some questions:

It would not be difficult to spend your total machine budget on only tooling, I'm sorry to say. TonyStark pointed out basic tooling and work holding costs, which is really only the beginning! (don't let this statement deter you though -- you can find a way!)

example:
I'm semi-retired, and have a Haas Super Mini Mill in a small shop. I just did a quick count on tool holders: I have mostly Techniks holders that I bought new in ER16 and ER32, along with maybe 30-40 collets. I also have 2 drill chucks (one 3/8" and one 1/2"), one Schunk hydraulic chuck and two face mill arbors. 17 in all, and even though the SMM only holds 10 tools, I end up using just about all my holders at some point. Maybe around US$3000+ for all that. I have a few vises (one Kurt, one smaller precision vise), and also have other various small clamping methods... maybe another US$1000-$2000.

None of the above addresses actual cutting tools, which can get expensive especially once end mill size goes over 10mm and you're purchasing high quality tools. Face mills and inserts can tie up some money as well.

When you say "tool setter", do you mean a presetter for setting up tools outside the machine? If so, I would not bother. I use one of these (Pro Touch Off Gage 4- - Edge Technology), and can set tools up very quickly and accurately with it. Plenty good enough.

So to take a sweeping guess -- you could probably tool up with new/mid-range tooling for US$4000-5000, and possibly half that much (or maybe even less) if you purchase used tooling and "get by" with fewer holders. Once again though, the actually cutting tools can devour a lot of money!

Now to questions:

The large part you mention -- is there any reason it couldn't be done on a small machine and "side-stepped" once to obtain the length? Would the part have features you could reference after shifting the part? The issue I can see with doing this is the 500mm direction... buying a smaller less expensive machine may be a bit of a challenge if you require 500mm in the Y direction.

Also... you talk about taking a 150kg blank to 1 or 2kg. Can the bulk of the material be removed by any other method? Water jet possibly? Any through-holes in the piece?


Finally (in my opinion), if the goal is to run your upcoming CNC mill with any sort of efficiency, learning CAD and CAM is key. Autodesk Fusion 360 is probably by far the most reasonable and easiest "package" to jump into, and there is a huge amount of online help.


PM

 

[Tam.]

Thanks for the replies so far!

Have you priced the infrastructure stuff you will need like power?

3PH is easy to come by in the small unit I'll be renting, no problem. I'll need to double check that it's a large enough supply, but I think it should be fine. Clean, dry air is the only other infrastructure-ish thing (other than the basics of light, heat, water, etc) that I'm aware of - just a case of getting a decent compressor and drier, right?

And you want to program it manually?

I'm definitely planning on using CAM - certainly for the large parts I mentioned. I've got over 10 years experience in CAD already, so again it's just the CAM side I need to learn. I've got trials of a few packages on the go already. Also I'm lazy, in a sense, so I'll be making sure I get a machine to do as much of the leg-work as I can on the programming.

Autodesk Fusion 360 is probably by far the most reasonable and easiest "package" to jump into, and there is a huge amount of online help.

Certainly from a pricing standpoint Fusion 360 is the one. Annoyingly it's got an issue with the graphics card on my home computer, so I need to tinker with that before I can get going even!

The large part you mention -- is there any reason it couldn't be done on a small machine and "side-stepped" once to obtain the length? Would the part have features you could reference after shifting the part? The issue I can see with doing this is the 500mm direction... buying a smaller less expensive machine may be a bit of a challenge if you require 500mm in the Y direction.

I had considered this, but figured that even if I could move the part accurately on a fixture plate, or clock back in accurately (could machine some sacrificial features for this purpose), I'd be running into problems of the overhanging portion of the piece interfering with the enclosure etc... I guess that can be worked around, but it would be nice to not have that on top of all the other things which could go wrong on that piece.

I can remove the vast majority of the material from the big billet by water jet...even a fair portion with a saw. Like I say, this is a pipe dream project; I know there are a lot of hurdles for it, but I'd like to be able to give it a shot rather than investing in a machine which makes it even more of a headache at best.

I've got a spreadsheet going with all the major items I'll need approximately costed out, so I can see at a glance what the inital setup cost might be. Embarrassingly I did forget about vice(s) in there, so I've added an allowance for that now... Holders etc I'll try to pick up used where possible/needed. Good to know that 12+ is a quantity I should be aiming for, thanks.

I wouldn't go any smaller than the VF2 if you end up with a Haas mill.

Regardless of how much hp is actually output I don't think there is a geared transmission so low speed cutting will be done with dismal torque just when you need it the most.

I thought it was just the VF0 that didn't have a gearbox? Is there a reason other than size that you wouldn't go smaller than the VF2?

When you say "tool setter", do you mean a presetter for setting up tools outside the machine? If so, I would not bother. I use one of these (Pro Touch Off Gage 4- - Edge Technology), and can set tools up very quickly and accurately with it. Plenty good enough.

Yes, sorry, tool presetter. I've seen those touch off gauges around - I'll probably just stick with one of those then. I was thinking of also picking up a part probe like a Haimer, so I can clock in stock/parts quickly, as well as touch off a reference block on the table (where I'd have my touch off gauge) so that tool length & Z offsets are simple.


Anyone get some more UK-specific machine knowledge?

How about the cost of moving a machine in the UK? Some machines I'm looking at would need to be moved most of the length of the country - does that get expensive really quickly, or not add much over the initial call out fee? Anyone know that one person I should call about this?

Also how about support? I know that's a fairly regional thing in the UK too, but are there any MTBs who have awesome support in the UK/south west? Mazak's EU plant is only a 2h drive from me - that sounds pretty useful??

Thanks again folks

T

 

[706jim]

Anything smaller than the VF2 is likely going to have problems with Z axis travel. And if you consider an older machine where the tool changer isn't side-mounted (umbrella style), the magazine can interfere with your work envelope.We have a fairly new VF2 (2009) and it has no high/low gearbox. No problem with small cutters at high rpm, but not great if you put a decent facemill into it for cutting steel.

 

[Tam.]

Good shout - I hadn't really considered tools other than the one in the spindle getting in the way of what I'm working on...another factor to bear in mind!

Cheers,
T