Quick accurate & clean trimming of 6000 series aluminium sheet?

[julianf]

I cut parts out of 1.5 to 3mm anodised aluminium sheet on a cnc mill.

My problem is that, when the part is separated from the sheet, it can catch on the cutter, and spin off / get scratched etc. (cosmetic finish is essential for my customers)

So, i generally program the job to leave, say, 0.6mm of material, and then cut the last bit, whilst at the machine, so as i can handle the parts away as they separate. This is very dull. The machine is exposed, letting noise out, and cutting fluid all over me, etc.


So, im thinking of buying a saw that could do the last part of the job.


Ive been wanting a varga ( for some time, but theyre about £2k new, and come up 2nd hand so infrequently - and then the last time one was on ebay (about 2 yrs back) i was skint at the time.

Dealers have them, used, for about £800, when they have them, but, realistically, £400 or so is probably my limit to save myself a bit of a job that i dont like.

This is one of the varga saws -

They dont look like £2k worth, but theyre accurate, and give a perfect cut.



Ive also been looking at Proxxon FET saws -

I dont know much about them, but they seem to be popular with model makers. They have micro adjustment in 1/10ths of a mm, but you never know if that's actually somthing real, or just somthing thats written on the knob. What i mean is, repetability, lack of a load of backlash, etc.etc.

Theyre more like £250 new, so a whole load cheaper, but cheap does not necessarily mean good value.


My other option is to just build a tiny table saw, which im sure would be possible, but i have enough to be getting on with at the moment, and i dont think it would be worth it (as in the time vs money saving aspect)


So, the question -

Anyone have any experience with either of these, or similar, or just have any other comments at all? : )

 

[Wendelspanswick]

I cut parts out of 1.5 to 3mm anodised aluminium sheet on a cnc mill.

My problem is that, when the part is separated from the sheet, it can catch on the cutter, and spin off / get scratched etc. (cosmetic finish is essential for my customers)

So, i generally program the job to leave, say, 0.6mm of material, and then cut the last bit, whilst at the machine, so as i can handle the parts away as they separate. This is very dull. The machine is exposed, letting noise out, and cutting fluid all over me, etc.


So, im thinking of buying a saw that could do the last part of the job.


Ive been wanting a varga ( for some time, but theyre about £2k new, and come up 2nd hand so infrequently - and then the last time one was on ebay (about 2 yrs back) i was skint at the time.

Dealers have them, used, for about £800, when they have them, but, realistically, £400 or so is probably my limit to save myself a bit of a job that i dont like.

This is one of the varga saws -

They dont look like £2k worth, but theyre accurate, and give a perfect cut.



Ive also been looking at Proxxon FET saws -

I dont know much about them, but they seem to be popular with model makers. They have micro adjustment in 1/10ths of a mm, but you never know if that's actually somthing real, or just somthing thats written on the knob. What i mean is, repetability, lack of a load of backlash, etc.etc.

Theyre more like £250 new, so a whole load cheaper, but cheap does not necessarily mean good value.


My other option is to just build a tiny table saw, which im sure would be possible, but i have enough to be getting on with at the moment, and i dont think it would be worth it (as in the time vs money saving aspect)


So, the question -

Anyone have any experience with either of these, or similar, or just have any other comments at all? : )

Yandles in Martock are Proxxon dealers and they have a showroom with the kit that they will demo. Just off the A303 North of Yeovil.
Not the cheapest place but a good selection of machinery.

 

[Shox Dr]

If a table saw will do the job, then a clarke would fit the bill. I've this one, good bit of kit. That Proxon stuff looks a weedy to me

 

[Fergus]

Axminster Tools also keep Proxxon kit on the shelves

 

[scott0031]

I'm a little unsure why you are not doing the machining process a bit differently to make your life a bit easier. I hope you don't mind if i make some suggestions on the machining side and forget about the saws you are talking about. It's not my intention to teach you how to suck eggs so i hope you don't take offense. Without knowing the full set up you are using I can only base on common practices with the machining process.

1) Use tabs. If you are looking at a saw to trim the parts then they must be all straight lines (assumption) If so use tabs, its a bit more programming but worth it to save a lot of hassle. When the parts are cut, pop the sheet off the machine either knife the parts out or pop them out with your fingers and a rub with a rubbing block and the jobs done, while the machine is cutting the next lot. Tabs is a standard practice for jobs cut out of sheet that you don't want flying about or damaged as they break free.

2) Don't have your program so its showering you with coolant! If you have, as you say .6 left or so, what coolant is that's left in the channels you cut will be totally ample to do its job on such a small cut. If you are not happy with that just use a hand mist sprayer and a give the work a few squirts. Again, totally ample to do its job with something like that and you wont get showered! But if you use tabs then you wont need to worry.

3)If you don't want to use tabs for whatever reason, then where a part is located use a bit of double sided tape, you can get very good tapes these days that are resistant to oils and coolants and grip very well indeed. This will be ample to hold even small parts for a final cut. I use this method on hard to hold parts like plastics. I often hold thinner plastics this way as vices can bell the work and you don't attain a lot of grip. I use this method to hold parts as small as about 20 mm diam, then machine. The odd one will let go but the time and hassle saves is no issue having the odd bit of scrap.

4) Think about having the parts water jet cut if its suitable for your parts and just sell them on and take your money. Water is super fast on thin easy to cut materials like ally. CNC machining generally can't compete with water jet on simple 2d parts. They do not have the difficulties of holding the work, cutter forces or cutters to buy etc. It's worth a thought. I now often put out simple multiple parts to water cutters, as it will cost me more to machine the parts. Take a cut and get on with some other work.

I hope you find this helpful.



Kind regards,


Scott

 

[julianf]

Thank you for the reply,

Ive tried to implement tabs before (as in a long time back) but have not managed to do it, and, in truth, probably gave up too soon. As you say, these would be the ideal solution, if i could get them to work. Your mail has made it clear that i need to re-visit this - you know how it is, somtimes you cant get somthing to work, so you find a work-around, and then get too used to the work-around to ever properly resolve the original issue!

Coolant flow is manual, but even drips still leave you (me) splattered in sharp wet alluminium swarf... But this should be a moot point anyhow, as there shouldnt be a need to sit over the machine.

If i cant get the tabs to work, then the tape option will certainly be somthing to look into - do you have any brands, etc. that you might point me to?

Outsourcing probably isnt viable, as its low volume custom 1-offs etc that i panalise, and run. By the time ive driven the part--finished job over to a water jet place, i may as well have just sat and babysat my own machine.

Thanks again for everyones comments.

 

[Nelis1900]

Using tabs or tape I've found both very useful. If for some reason that won't work you could maybe use a toggle clamp you clamp down half way through the job. And if the jobs have holes in it another option but maybe to time consuming is to have a hole block(a block full of small threaded holes) and bolt it down with a penny washer.