Horizontal/vertical wet saw machines

[jc1104]

Hi all,

I have a finish quality issue with my process whilst using a horizonal wet cutting saw to part to length a tube of quartz glass.

Quality issues are: finish cut chipping on inside bore, cut not always square, diamond blades are 'walking'.
Quality of finish only occurs on tubing over 200 mm (approx 8")

The blade is the best-of-the-best, has been stiffened to reduce walking, is regularly cleaned, sharpened and replaced when worn. The feed rates are okay as well.

Therefore, I am down to equipment and would like some assistance on finding a process/manufacturer that can supply equipment that can do this task.

Maximum tube diameter is 400 mm (approx 15.3/4").

Any help is appreciated,
JC

 

[unclesyd]

Are you using the cut pieces as is or is thee secondary operation like diamond lapping?

Is your thickest section the 15" or so dimension mentioned in the OP?

Two things I Know that can give the type problems in OP. The first is the cutting fluid which I've found out has to be extremely clean preferably new on each cut. It also might be noted that there is vast difference in fluids. composition and viscosity being fore most.

The second problem I've seen is the in-feed is very critical. I've found no universal feed rate. Using different type blades will normally require changing the feed rate, The same holds true with the different cutting compositions.

Years ago when the 8" Silicon Boule started coming out of the furnaces the existing cutting procedures for the smaller Silicon Boule were unsatisfactory. Diamond wire machines were just coming on the market and I was lucky enough to get them to try one. We used a reciprocating wire machine as the the endless wire machines hadn't come on the scene.

There are numerous manufacturers of Diamond Wire Machines with Well having good cross section of machines.

http://www.welldiamondwiresaws.com/have/Diamond Wire Saws News!.htmffd

 

[jc1104]

Thanks for the reply Syd. I'm on my way to check out the diamond wire saws right now.

The quartz tube is hollow. for example, outside diameter of 300 mm, inside diameter of 284 mm, giving a wall thickness of 8 mm.

Currently we have a horizontal bench mounted saw, with rollers to support the tube (which can be 1 metre long).

Our operators have to feed the blade to the o/d, then rotate the tube by hand for one full revolution, then feed the blade a little further until the tube is parted to length.

There are a lot of variables in there which singularly or cummulatively can be contributing to the problems, hence searching for automated equipment.

This should be our final operation, no additional lapping required, but I am finding that we are having to cut to max tolerance plus an additional 1 mm then mount the tube onto our flange grinder to final machine square and to an excellent finish.

Again, thanks for the response.

 

[racookpe1978]

But your saw is going through vastly different material thicknesses and "relative entry angles" as it goes through the tube: Are you compensating your feed rate at the different steps of the cut?

You start with a horizontal cut with shallow entry angles as the saw begins. The whole length of the cut is engaged with the saw blade.

Then you get through the upper tube wall: You begin two cuts of thin-walled tubing. Far fewer blade teeth engage, and you get no cooling fluid at all on the far wall as the teeth enter the wall. If fluid flows at all on the side, it hits the teeth only after they have left the tube wall.

Then you get to the bottom of the cut: the teeth engage again all the way across the cut, but you have no lubrication at all.

Mark your tubing with "top" "bottom" "entry side" and "exit side" labels and make several test cuts.

Check your break through positions and the problems you are having with respect to start, middle entry, middle exit, and lower cut. You may see a pattern where some method of "inside" lubrication is needed.

 

[powerhound]

The way we used to cut quartz tubing to length was with by rolling the tube on what was effectively a table saw. Of course we took all sorts of measures to ensure a scratch free tube but it was a quick process with virtually no chipping on any size of tubing. We cut tubing well over 300mm on a regular basis.

Powerhound, GDTP T-0419
Engineering Technician
Inventor 2010
Mastercam X5
Smartcam 11.1
SSG, U.S. Army
Taji, Iraq OIF II

 

[ornerynorsk]

Back when I used to mess around with lapidary equipment, the rule of thumb was to use the smallest blade possible, and running the "spent" cutting fluid through a filter pad before return to sump. Has your blade mfr done any recommendations or trial cuts regarding your RPM's? Assume you've checked axial and lateral runout of the blade disk?

 

[jc1104]

Thanks for the response.

Racookpe, the coolant is aimed at the edge of the wheel where it first makes contact. I'll see if I can get another loc-line to aim a secondary coolant jet at the inner part of the tube and see what difference it makes. I like the idea but not sure it will make much difference as the wall thickness is around 8 mm on the large diamter tubes that the blade isn't really cutting a first and second wall like you mention. Perhaps I should have mentioned that we rotate the tube to eliminate and not pass the entire tube through the blade. Apologies for the confusion.

Powerhound, at present that is exactly what we do. We roll the tube by hand through the table saw. Smaller diameters don't present a problem, however, our high value high spec large diameters do create chips and cracks. From this we have to cut a little bit longer than required and finish grind the face.

Ornery,
I'll have to check up on the coolant filtering and see what exactly is being done. We have tried various blade manufacturers, with some better than others. It is a fixed speed machine and I'd have to double check the actual surface feet per minute for each diameter wheel we use.
The axial and lateral runout is checked when fitted and as the wheel wears, we regularly sharpen and polish the wheel to clear out any glass build-up and to true the wheel again.

It's looking likely I'll be requiring a replacement piece of equipment that can handle the work. Any recommendations?

Powerhound, you mention yuo took all sorts of measures, can you kindly share a few and I can trial them to see what quality improvements I can get before spending on new equipment.

Thanks.