Heavily CNC converted Opti BF 20 Vario

[mattbesquare]

What especially you would like to know?

If you have a vise like that:
http://www.glacern.com/gsv_440
Copy the dimensions of the original jaws,
maybe make them little higher in Z- direction.
Machine those from thick aluminium, bolt them to your
vise, and then before you machine your parts shape to your
soft jaws: put something thin between your jaws before
you tighten your vise. It could be something like 0.5mm (~0.02 inches)
thick steel ruler, strip of thin sheet metal or something like
that. That will put your jaws apart something like 0.4-1mm when you
tighten your vise.

Then machine your parts shape to your soft jaws. Usually it's some pocket toolpath if you use cam. After that, you will
have your parts shape at your soft jaws. Open the vise, throw
that piece of thin sheet metal away, and there you have
your parts shape at your soft jaws, and also enough gap
between the jaws so that you can tighten your parts well.
I hope that explanation makes some sense. I would have put couple
pictures, but I forgot my camera to my workshop.

Another possibility is to make thinner soft jaws, which lower
part will fit tightly to the slot at the center of the vise.

>you seem to have a set for every part you make?

I would rather not make soft jaws all the time, but
it just seems that all the parts I make will require them

I like that "impression" method of making a repeatable soft jaw groove for your parts. Kinda how sitting long enough in my chair makes it conform perfectly to my...er body.

Maybe with the next chair I will find some steel rules and compress myself into it-might speed up the effect! :-)

[JMI80]

JMI80
Just curious, on the 2nd side of the wheel, why not use the fly cutter on the other side instead of the rougher (I believe it was the same rougher from the other side.). Seeing the final product, I am sure you had a good reason.

One reason is that I don't have fly cutter...
It could work just fine, good idea!

I tried to use 40 mm face mill, but part starts to vibrate/ flutter like there's no
tomorrow. It's only 1.3 mm thick at the center, so I was expecting that but I had to try. Finish cut is made with regular 10mm, 4flute HSS end mill.

What do you use for chamfering? 90 Degree endmill?

It's regular 90 degree NC- spot drill. There are especial 4-6 flute solid carbide chamfer mills, but I have not bothered to buy one since I make so small amount of parts. Also when there's no automatic tool changer I try to
use so small amount of tools as possible and avoid manual tool changes. I try
to find multiple tasks for each tool if it's possible.

[digits]

What especially you would like to know?

If you have a vise like that:
http://www.glacern.com/gsv_440
Copy the dimensions of the original jaws,
maybe make them little higher in Z- direction.
Machine those from thick aluminium, bolt them to your
vise, and then before you machine your parts shape to your
soft jaws: put something thin between your jaws before
you tighten your vise. It could be something like 0.5mm (~0.02 inches)
thick steel ruler, strip of thin sheet metal or something like
that. That will put your jaws apart something like 0.4-1mm when you
tighten your vise.

Then machine your parts shape to your soft jaws. Usually it's some pocket toolpath if you use cam. After that, you will
have your parts shape at your soft jaws. Open the vise, throw
that piece of thin sheet metal away, and there you have
your parts shape at your soft jaws, and also enough gap
between the jaws so that you can tighten your parts well.
I hope that explanation makes some sense. I would have put couple
pictures, but I forgot my camera to my workshop.

Another possibility is to make thinner soft jaws, which lower
part will fit tightly to the slot at the center of the vise.

>you seem to have a set for every part you make?

I would rather not make soft jaws all the time, but
it just seems that all the parts I make will require them

Thanks for the detailed reply

I guess what I was wondering was how you come up with the tool paths for the jaws when you want to clamp something of fairly large diameter without having to make jaws of the same total thickness as the width (Y-dimension) of the parts. I guess it's not that hard to cut a chunk out of the middle of your part's CAD model, use what's left to make an inverse model for the jaws and then feed that into your CAM tool...

Or I suppose you could even machine the soft jaws with the vice open, but clamping something wide but below the Z of the cutter, using a full part-width toolpath...

[JMI80]

Thanks for the detailed reply

I guess what I was wondering was how you come up with the tool paths for the jaws

I suppose you could even machine the soft jaws with the vice open, but clamping something wide but below the Z of the cutter, using a full part-width toolpath...

That's just the way these jaws were done. I clamped parallel between the jaws, below the Z level of the cutter toolpath. I attach couple tool path pictures. Very simple, some pocketing and profiling toolpaths. Pics are from Visualmill demo, I'm training and playing with that.

Program does maybe minute of air cutting, but it doesn't matter anything when it needs to be run only once. Things would be different and more program optimisation is needed if 100 or 1000 pieces needs to be done...

[Nava]

You put allot of work and thought into making the bf20 something other than cheap Chinese garbage I have one and I'm seriously considering doing what you did with the linear rails because even though the machine was great new the sideways are already starting to be banana shaped after 6 months of light use because of the long table and gravity. Is there any chance you would consider telling us more specific details about the parts used type of steel used to make the supports for the rails and if at all possible DXF drawings of what you did would be awesome. I think given those things we may see another whole generation of bf20 and G0704 upgrading and modding. I have the chance soon to possibly work with an more experienced engineer from Germany to learn scraping, it would be a great opportunity to perhaps do this at the same time and document the process. Anyway congrats again its a nice machine.