Has any one cut Polypropylene?

[Scott Marshburn]

We have a customer that is wanting us to surface sheets of Polypropylene. I was wandering if anyone has cut this material before? If so what feeds do you suggest. The cutter we will be using is approximately 1 7/8 in. diameter. We will most likely be using our fly cut program to surface the material.

[Daniel Odom]

Any reason why? I Haven't cut Polypropylene yet but have cut some 1 inch thick UHMW. I'd look at the chip loads for a large diameter double o flute and go from there, as long as you aren't going very deep I don't think you'll have too much of a problem. The material may try and curl on you though. I'd prob. just flycut as you normally do, just drop the feed rate down to 60% and only cut 1/64-1/32 deep at most and see what it does. After a pass or two you should be able to tell if it's working or not; obviously keep the e-stop near by when cutting a new material or with a new tool. Your tooling manufacturer may be the best one to talk to though.

[Scott Marshburn]

Hi Daniel Thanks For your advice. We did a test yesterday morning and it went well. I made a copy of our fly cut program and changed the spoil board dimensions to the approximate size of the sheet that we cut. And also changed the rpms to 18000. I was able to go .03 inches per pass at 1200 Ipm.At 600 inpm it did want to curl.
Now if I could get the program to prompt the user to input the X&Y dimensions of the material and change it automatically (Sort of like when it ask for the touch off and the amount to remove)That would speed up the set up time as we will be surfacing various sizes.

[Daniel Vonderheide]

Scott,

We do offer custom programming. if you send a Request for quote to program@thermwood.com, I will send you a quote for adding in the prompts for width and length.

[Scott Marshburn]

Tanks Daniel or your response I will make a wish list and present it to the boss. Maybe we will get back to you soon

[Marius Gouws]

Good afternoon ,Scot
I have modify the original fly-cut program, so it ask you the length(x-axxis) and width(y-axxis) of the material you want to fly-cut. It works from the G902, so your material must be in the fence location.It works like the original program, the machine index over the table, you get your Z touch value, hit clear on your handheld programmer, machine go back to Z0, push the green button, machine go back to home, ask you for the Z touch off value, and then how much you want to take off. After that ask you for "Length" and then "Width", and off you go (Bobs your uncle)
Hope it help
Marius
PS Our machine is metric
Use at your one risk
We have a 58mm diameter flycutter, the step-over is set to 40mm(you can change it in the program)
My flycut tool number is T990, if yours is different you must change it in the program

[Scott Marshburn]

Thanks Marius I will tak a look at it when I get a break

[Scott Marshburn]

Marius our machine is imperial what changes should I make other than the cutter and step over? Also do I need to set the Tool up in the tool manager In other words will the machine try to locate and do a tool change?

[Marius Gouws]

Good Morning Scot
Imperial!! Then you are going to have to make more changes. My tool 990(fly-cutter) is in the same tool holder (B1) than my tool number 1(T1). If "T1" is not in the spindle head, I do the following:
F5, F3..(new part program), give it any name, then hit "enter"
F1, F5..type "T1" then hit "enter"
F1, F5..type "G90" then hit "enter"
F1, F5..type "G990" the hit "enter"
F1, F5..type "G00 X0 Y0" hit "enter"
Go to the top of the program code, and push the green button. Now after the tool change I have tool 1 in the spindle head. Next "E-Stop" and turn the "Tool Lockout" switch. I take tool 1 out of the tool holder and put my fly-cutter in.Home the machine and run the tool length program.Like I said tool 1 and tool 990 is in the same tool holder, in the "Tool_len.nc3" program I select "T990" then "do It". Tool number change to 990 and I measure my fly-cutter. Now I run the fly-cut program. When I am finish, I take the fly-cutter out put tool 1 back and do a "rebuild"
In the program go to line:22, that T990 you must change to what ever your fly-cutter tool number
Line:24, that values is in millimeters , must change it to inches ( 800mm=31.4ich) 1inch = 25.4mm (change X, Y and F)
Line:25, the same conversion
Line:63, step over is 40mm, change to inches
Line73, the value "25" must convert to 0.98inches
Line85, T990 to your fly-cut tool number
Last, the lines that follow you must change the feed rates to inches
I do not want to lead you into doom, just check with one of the Thermwood oaks, maybe if you just put a "G70" in the beginning of the program it will convert to imperial automatic.
Cheers
Marius