[jemmyell]

Hi, I found this diamond wire online. I want to make a diamond wire saw to cut slabs of reconstituted stone. The blocks are about 2.5" thick by about 6.0" wide by about 8.0" long. I want to be able to make 6.0" x 8.0" slices with very little kerf loss. This is a composite of crushed stone and epoxy so it is not too hard. I have been cutting sheets of it on my CNC with carbide microtools. I mostly make inlay parts for woodworkers from it.

http://www.mtixtl.com/index.asp?Page...ROD&ProdID=461

The CNC part seems pretty easy, it is the design of the wire handling assembly that will present some challenges.

-James Leonard

[Oldmanandhistoy]

http://www.mtixtl.com/index.asp?Page...ROD&ProdID=461

The CNC part seems pretty easy, it is the design of the wire handling assembly that will present some challenges.

-James Leonard

Hi,

Have you considered reciprocating the wire, similar to a scroll saw?

John

[jemmyell]

Yes! The assemby should be reciprocating, but it must be horizontal and able to accomodate a width of up to 6-8 inches. Any ideas / drawings / links?

-James Leonard

[keebler303]

Maybe something like this?

http://staff.um.edu.mt/ccam1/hacksaw1.jpg

Its a power hacksaw. I would think you could make something similar to do what you want.

Matt

[jemmyell]

The reciprocating mechanism needs to accept spools for diamond wire. There needs to be an easy method to rethread the takeup spool since I understand that wire breakage is not infrequent. Other solutions (rocksaws, etc) waste a MAJOR amount of this material due to kerf losses.

-James

[High Seas]

Here's an idea - maybe make/mod a machine that uses a ring saw - kinda like a band saw but with a diamond blade. These are use for cutting glass - may have a bit more kerf than you are looking for - but the tool is ready made:
http://www.diamond-drill-bit-and-too...s-Ring-Saw.htm

Some of the blades are thinner :
http://www.diamond-drill-bit-and-too...s-Ring-Saw.htm
Cheers - Jim

[jemmyell]

I have looked at the saws for the stained glass cutters, both ring saws and diamond bandsaws. The kerf width is acceptable, but the capacity is not. The blocks of recon stone I can get are about 3" x 6" x 9". I want to take slices in the 6" dimension to yield sheets .150 thick x 6" x 9". I can get smaller sheets out of these larger sheets. At this point I can only cut in the 3" dimension with a .125 diamond saw blade (rock saw). Horrible kerf loss and the 3" x 6" slice is not really good for many of the things I wish to make.

-James

[BillTodd]

Looking at the precision wire saw on that web site; It looks like the large drum holds a few metres of wire (presumably both ends fixed to the drum) I'd guess it revolves a few times one way then reverses. All the wire guides have to roll. Doesn't look too difficult to make (the devil, of course, is in the detail).

I suspect controlling the wire tension is the most important thing.

What about using two drums with servo feedback to the drum motors? - like a tape recorder

[jemmyell]

Yes, in this case I am favoring a moving table design and a fixed gantry to hold the spools and the motors to move the wire. It is probably desireable to do this wet so no MDF can be used. I am undecided on how to mount the block for cutting, any ideas? Ideally I would like to cut the entire block without repositioning, but that may not be practical.

-James

[BillTodd]

I am undecided on how to mount the block for cutting, any ideas?

You could save yourself a lot of time by buying a cheap X Y drill vice or, if you want something a bit better made, a small XY milling table*, to hold the block. You then have to modify one axis for a stepper (shouldn't be too difficult)

I'd guess the motor gantry could get quite heavy, so a pair of linked lead screws at each end of the gantries Z axis would be in order. The slides need not be too accurate, so V rollers onto a vertical tubes or rods would do.

Actually, if you're cutting wet then perhaps it may be better to have the rock fixed, in a deep tray, and a 2 axis **(X/Y and Z) gantry high-up to keep the slides clear of the abrasive slurry

[edit] */** I wonder if it would be possible to use a cross slide like this vertically (single sided) to give you X/Y and Z axes. Imagine the gantry perpendicular to the table.

[jemmyell]

Ok, that's an idea! Harbor Freight has a cross slide vise that seems like it is maybe big enough.

http://www.harborfreight.com/cpi/cta...emnumber=32997

I will have a look. They have many stores close to me.

This will give a me a mount and lead screws. Now I need to get a stepper motor hooked up.

THEN the diamond wire reel mechanism...

-James

[Oldmanandhistoy]

This is a composite of crushed stone and epoxy so it is not too hard. I have been cutting sheets of it on my CNC with carbide microtools. I mostly make inlay parts for woodworkers from it.

Might be a silly question but have you considered casting your own at the required thickness?

John

[jemmyell]

No question is silly!

BUT, I want to USE recon stone, not make it! The main supplier of this makes a fine product. I just need to make sheets so I can make inlay shapes for musical instruments and fine woodworking. I did have a supplier who was cutting sheets, but they were very small and he did a bad job also. I have a rock saw, but it is wasteful and cannot cut the sheets I want.

-James

[BillTodd]

Some further thoughts on the wire cutter. (from my experience with tape recorders)

i) keep the drums/reels and guide in the same plane as the cut (i.e horizontal ) it'll simplified the wire transport.

ii) use the largest possible diameter drums and guide wheels, to keep the minimum bend radius as large as possible.

iii) the feed rate should be controlled by the wire tension, so that if the wire starts snagging the feed slows. I'd use a small DC motor for the feed with simple analogue feedback from a tension sensors.

iv) minimise the mass of the drums, so if wire snags the momentum of the drive drum will not break the wire.


I'd use two simple servo sections. One on each of the two drums motors i.e. a potentiometer/spring measuring the wire tension just in front of each drum. As the tension increases so the power to the motor should be reduced. Simply changing the gain/bias of the servo loop (or the tension of the spring) will drive the wire in one direction or the other.

[jemmyell]

I'm now looking at just tensioning a wire segment between two posts and moving the wire back and forth rapidly. Either an air or electric linear actuator. Maybe make the posts spring loaded for easy wire change and then use the actuator(s) to push this back and forth?

That should give me an assembly light enough to suspend upside down ultimately. The z depth would allow moving through the block as sheets are cut. Maybe I can even devise a cut sheet removal step tied to the return of the table.

-James

[BillTodd]

Surely, a short length of wire will be subject to increased wear rate and possible heating, leading to premature failure. There must be a reason why the commercial machines use many metres of wire.

I think you should test your idea manually, with something like a hacksaw frame to see how the wire stands up to repeated use.

[keebler303]

I'm now looking at just tensioning a wire segment between two posts and moving the wire back and forth rapidly...

As I mentioned in Post #4, a power hacksaw does precisely that. The design is dead simple.

Matt

[keebler303]

Surely, a short length of wire will be subject to increased wear rate and possible heating, leading to premature failure. There must be a reason why the commercial machines use many metres of wire.

I think you should test your idea manually, with something like a hacksaw frame to see how the wire stands up to repeated use.

I don't think the wire will wear any more quickly. You will have to change it more frequently, but the square inches of cut should be the same for 1 foot or 20. The 20 foot piece will just last longer between changes.

Water is a necessity for cooling, so heating of the wire should not be a problem.

Matt

[jemmyell]

One of the things that makes me want to explore the single wire design is that Harbor Freight is selling diamond wire scroll saw blades for $1.00 each (plus shipping of course). This appears to be a really inexpensive way to prototype the idea before buying a reel of the more expensive wire.

http://www.harborfreight.com/cpi/cta...emnumber=32347

I need to suspend this wire between two posts that will hold the wire in tension but allow the assemby to move back and forth when one post is pushed from the outside. I'm hoping that spring loading the posts so that each is pushed in to half travel will allow the opposing spring to push / pull the wire.

other ideas?

-James

[BillTodd]

One of the things that makes me want to explore the single wire design is that Harbor Freight is selling diamond wire scroll saw blades for $1.00 each (plus shipping of course). This appears to be a really inexpensive way to prototype the idea before buying a reel of the more expensive wire.

OK Yes that make good sense.

I think I'd try Matt's power hack-saw design rather than a spring retur. How about a car windscreen (windshield) wiper motor for power? It might even have a crank ready to go.