Cutting Ceramic Tile ô¿ô

[lockeyone]

Cutting Ceramic Tile
Ok, I am in the process of cutting some ceramic tile a friend gave me. Since he donated it he asked for a Harley logo. I had drawn one of these years ago learning BobCAD. So I brought it into VCarve and I am now running it. I am using a 1/2 inch carbide V bit. Don't remember where I got it. I set up the program to cut a depth of .02 inches at 2ipm. Pretty slow but I am cautious. After a bit I brought the speed up to 4 ipm and even tried 5. Almost right away I knew this was going to be a long test. The 2 tiles I was given are both low in the middle. You can see in the pics what I mean. I didn't' spend my whole time watching this. About a 14 hr run. I have a networked camera in the garage so I can watch/listen to what's going on. I wanted to buy the camera with zoom but the price jumped considerably for that feature. So if I am not in the garage I am usually found on my computer. So I just listen/watch while working/playing on the computer. It is amazing what just listening does. If there is a change in noise I look at the camera to be sure things look ok. If its making noise its working, if it gets quite, did the bit break or what. So I stayed on edge most of this 1st run.
I took pics of the router bit after the 14hrs. Actually I was expecting a dull bit. Not so. Looks pretty good to me. So I reinstalled it. Set my 0 depth to the center of the tile and re-ran the program. Definitely a deeper/harder cut. I slowed the machine down to 1 imp because I could feel more vibration. This one's going to take awhile. I also took pics of the bit while running on this deeper cut. You can see the tip red hot. In my business when I have to drill open some of the high security safes I have to get my drill bits this hot it not more and I always manage to get through some pretty nasty hard plating. I thought a lot about coolant etc., but decided to run without to see how things go. I learned from drilling safes that you either use it from the get go, or not at all. If you introduce coolant of any type after the bit is hot it just ruins it right away and renders it useless.

Last pic is a screen shot of what I get to look at. I had to put a small light on it last night to see the router. Didn't want the garage lights on all night.
If you want to here the noise I had to listen to click here. http://www.lockeyone.com/pics/vcarve/tile.wav I just recorded it right of the computer in my office. I have got to get that zoom feature. Or at least get another camera (macro) to watch the bit while its cutting.

The only holding method is the vacuum table I built. The tile has a rough surface on the back, this system did a nice job sucking the work piece down.
1st run:










Ok, I finally had to all it quits on this run. The tip of the bit just eventually burned away. I had thoughts of different ways to cool this. One is a cold air blast which I read about somewhere on the cnczone. May have to check it out. I also thought about making a small water tank to set the piece into, to just either flood or mist the bit or even just submerge the piece. There is a lot of down blast of air from the router and I was hoping for enough airflow between that and the vacuum setup it might work. The results look promising. I think the effect of the cut tile would be nice and have some potential but have to work on some different techniques. The router motor after a very long run was cool to the touch. Hmmm, what can I try next.

2nd pass:

[skippy]

nice job! What about making up a simple bath with the tile inside below the line of the water or chosen liquid. Bath held down by vac bed and tile held mechanically (screws, clamps, etc) At least your spoil board would be protected that way.

p.s. how bout giving the rest of us some Safe drilling tips in order to help our pension schemes along? (or lack of pension schemes) hehehe!

[lockeyone]

My one concern is the low spot on the tile. I suppose if I find a nice way to cool the bit I could use a 60 degree v-bit.

As far as safes, if I told you I would have to kill you!

[skippy]

V bit will give you varying cut widths due to the changing surface height of the tile.
The rough (fast + easy) way to finish the job is: on the computer eliminate the parts that are already done leaving say a 5mm overlap and redo just these sections at a lower cut height and if need be do the same again to the section at the very centre. This is assuming you are doing one or two and as I said, it's the rough way. If you want to do it properly it will have to be done in 3D by measuring the surface height at various points using a grid then insert this data into your cad program. Whether you have 3D cad/cam facilities I don't know.
I used to have a similar problem when engraving wood planks for national parks in that the surface height of every plank changed from one end to the other leaving two possibilities: deep engraving (not possible in your case) or the cheat's method. In my case, I had at that time a pneumatically controlled Z axis and so I fabricated a ring (for want of a better word) which encircled the cutter. It was similar to the base of a plunge router but smaller and with radiused edges made from hdpe. The ring would lower with the Z axis and contact the job meaning that the Z axis height changed with the surface height of the job. (Z axis limit switch was an adjustable pressure switch)
Crude but it worked.

[spider]

indicate the tile verticaly (both sides and middle) and horizontaly (top bottom and middle. Use that to crate 6 splines in appropriate location and then project your part onto it......remake the cutter path, and recut....

see attached pic....

[beone]

What is your source of the v bits. I have found that most of them are actually two bits of carbide brazed in the shank. This leaves a weak spot at the very tip. Whiteside makes a one piece bit but are hard to get. Would appreciate knowing your supplier.
Dave

[lockeyone]

This bit must have came from either Ace Hardware (Bosch) or Sears (whatever?) but lean towards the Bosch. It is a 1/2" bit with 1/4" shank. Now is has a 1/8" flat.

[lockeyone]

Just thought I would drop a note. I was at my buddy’s auto shop and one of the mechanics over heard me saying something about a Vortex tube and he says we have one of those! They use it for checking choke systems on carburetors. Cool, I brought it home this weekend and played a little. It takes a lot of air flow and my compressor basically ran constantly and at a lower pressure than recommended. But if was worth getting my hands on one to play. After running about 15 minutes, my compressor settled at 6o lbs tank pressure and 50 psi output. The shop temps were 50 degrees, Vortex tube temps were 12 degrees cold side, 80 degrees hot side. I have a 4hp craftsman oil-less that is about 12 years old. Think this would be the project to break my compressor so I don't think I will use that method but sure was nice to get my hands on one to play with.

So if you know someone with and auto service shop, here's your chance to play before you pay. I ran into the MATCO Toolman later that day and he said it was $219.00.