Thinking of jumping into CNC milling. How to start ?

[m_c]

Fixtures for boxes should be relatively easy, and reasonably universal.

The hardest part will be coming up with some form of clamping strategy to give good support. If it was me and I was planning on doing lots, I'd be looking at some form of large open vice like setup, which allows the box to be stood on end/edge, and clamped on what would be the top/bottom (or front/back depending on if you class the lid as top or front).
Add in an end stop for locating the box against prior to tightening, and you've got a repeatable clamping setup.

For doing the clamping, some form of toggle clamp setup would allow for quick changes, but would need someway of being adjusted for different box sizes. If you really wanted quick changes, an air cylinder and valve would make things quicker, and cover a larger range of sizes without adjustment.

[magicniner]

Fixtures for boxes should be relatively easy, and reasonably universal.

The hardest part will be coming up with some form of clamping strategy to give good support. If it was me and I was planning on doing lots, I'd be looking at some form of large open vice like setup, which allows the box to be stood on end/edge, and clamped on what would be the top/bottom (or front/back depending on if you class the lid as top or front).
Add in an end stop for locating the box against prior to tightening, and you've got a repeatable clamping setup.

A two piece machine vice can offer a lot of flexibility with infinite variability in jaw spacing and the option to mount on riser blocks,

- Nick

[JAZZCNC]

For doing the clamping, some form of toggle clamp setup would allow for quick changes, but would need someway of being adjusted for different box sizes. If you really wanted quick changes, an air cylinder and valve would make things quicker, and cover a larger range of sizes without adjustment.

Like this you mean.!! . . . . Also Shows good example of why router is better suited than mill.



OR if prefer in aluminium.

[m_c]

Like this you mean.!! . . . . Also Shows good example of why router is better suited than mill.

That's maybe a little too advanced for Sparky, but certainly shows how the commercial guys do it.

One thing I did mean to mention, was you mention you get charged a fixture cost. It should really be referred to as a setup cost, as what you're really paying for is the setup time for the job. That includes checking your drawings, working out what tools are needed, converting them to whatever code the machine runs on, and setting the machine up to run your job (load the code, setup the required fixtures, and make sure the correct tools are loaded). Once the setup is done, it's just a case of loading boxes and hitting a button.
The actual fixture cost for somebody running these kind of jobs regularly will be very minimal per job. The fixturing shown in the videos Jazz posted will cost 4 figures, however that will cover lots of boxes with minimal changes between box sizes. It can be thought more of as a machine cost, rather than a job cost.

[JAZZCNC]

The fixturing shown in the videos Jazz posted will cost 4 figures, however that will cover lots of boxes with minimal changes between box sizes. It can be thought more of as a machine cost, rather than a job cost.

From Datron Yes but here in the real world same could be made for not lot of money. But this may better showtype of fixture I was meaning. Also one to see the difference between Mill and router.!!



Almost slow motion but not quite.!

[SparkyLabs]

I don't particularly need high speed or large batch manufacturing. I'm only wanting to do prototypes and very small quantities. I think too many boxes stacked up could increase the risk of error but even on a mill a few at a time dould be loaded. I have a box face of 90x30mm and a mill with a travel of 100*290mm can do a few.

[SparkyLabs]

ultimately flexibility will serve me more than speed. If I find that I need to do a particular job in large volumes and that a specific machine is best for this then specific machinery may be justified.

[m_c]

Those videos were mainly to show you how things can be done, and to give you ideas on how to mount boxes.
We know you're not likely to ever use such a big/complex setup, however it should give you ideas on how you could mount a single box, while making any fixtures as universal as possible.

If you look at the setup in the first videos, they use an extruded aluminium T-Slot bed to mount pneumatic clamps on. Using a T-Slot bed gives you easy adjustment, and the pneumatic clamps mean you get a wide clamping range so they don't have to be setup exactly. They just have to be setup to give enough clearance to get the boxes in, while making sure they clamp before running out of travel.
The pneumatics has the major advantage that a single valve controls the clamping of all the boxes.

To simplify that, use a T-slot base for the flexibility, and then use a two piece machine vice setup like magicniner has mentioned (first google hit - http://www.bison-bial.co.uk/vises/6522-200 to give you an idea of what we mean). Add in a block to the side of the vice to position the box prior to tightening, and you've got a repeatable setup for if you need to multiple runs.
With that kind of setup, you should be able to cover a very wide range of boxes.

[SparkyLabs]

Any comments on the Wabeco F1200 CNC ? this is like the proxxon controlled with nccad

[magicniner]

"by connecting the WABECO controller to a PC and installing
the nccad turning software the customer turns the conventional
WABECO milling machine into a CNC milling machine"

I hope they do better with mills than with proof reading because you won't get far with a mill if you use turning software! :-(