Question on Pirana

[Keith Hodges]

Helping my brother in law set up and find his way around using his new Pirana CNC. Bout got it all figured out, really frustrating using its control box, which is quiet a bit different, and less user friendly than the control box on my HD. Doesn't seem to be any step movement when jogging the gantry, just fast, medium, and slow. Slow is still to fast when wanting to set 0, 0, 0. A lot of jogging back and forth. Also, while carving, doesn't seem to be any speed control, and while doing a pocket, really plowing through the wood with a 1/4 inch end mill. Way faster than I do on my HD. Hard on the wood, the bit, and the gantry. Anyone that's been using a Pirana found any speed controls?

[4DThinker]

Not sure if this will help as I don't have a Piranha, but if there is a feed speed slider on the controller that may slow down the relative speed at each fast/medium/slow level. Just a shot in the dark.

4D

[Bob]

Keith,
Check on the different options in the pendant. Yes, you do have control over the jog speeds. One feature I like a lot is when you have slow set at .001, you can hold down the selector button and the bit will move in .001 increments until you release the control. You can also jog .001 at a time by releasing the button quickly.
Bob

[Keith Hodges]

Thanks Bob, I think I know where your talking about and will have him try it. But, my main concern is the speed of the gantry while carving. I don't see any way to slow it down while carving. I don't see any slider of any kind, just think it is too fast for a large bit. Really seemed to be straining to keep up.

[Mimbler]

Keith, do you mean carving while running a tap file? Or are you just manually driving the gantry while the router is on?
Mike

[sawdustjohn]

I'm new to the wonderful world of cnc routers. My first is a piranha. I've had it about a month now so I'm far from an expert. My router is a dewalt 611(1 1/4 hp). I don't know of any way to change the rate of travel while running a project. I run all my projects at 30 IPM and that seems to be an ideal speed for the piranha. Also very light passes to start. I will be hammering all you shark users while I try to decide which one is ideal for me. I will be upgrading to a larger machine soon.

[Rando]

There is (may be?) a "global" Feed Rate Override (FRO) slider in the control panel. That will slow things down, but....

The primary and correct place where the speed of moving the bit are controlled in the program that makes the toolpath. In the Vectric line of software, those "Feeds and Speeds" are set in the tool definitions. You can create many MANY tool definitions for pretty much any kind of bit you want, and you tune the speeds it moves through the material from those settings. Those then get built into the tap/GCode file during the toolpath creation, again in the Vectric software.

Getting good cuts, in whatever material, comes down to setting the correct feed (through the material) and speed (RPM of the router). There is a sweet-spot, and it sounds like you're "above" it. That is, trying to gobble too much material in either too little time (router motion is too fast), or with too few router bit teeth taking up the material (router RPMs too slow). At the other end, if you run the router motion too slow while the router RPMs are too FAST, the bit will effectively slide across the material, heating it and leading to darkened material (wood), or re-welded chips (aluminum, acrylic), and a much shorter tool life.

The subject you're looking to learn is just that: how to find a good F&S for the bit, the router, the rigidity of the machine, and the material you're trying to cut. It's like one of those Rabbit holes: you can go as deep as you want learning about them, 'cause that hole goes WAY down there.

If you're using, say, VCarve Pro, when you go to make the toolpath, you'll see the part where you can select the tool(s), up near the top. Once you select the type of tool you want, you'll find other important values like cut depth for each pass of the tool, how much the cuts should overlap each other, and how fast the machine should move in the horizontal plane (feedrate) or downward into the material (plunge rate).

There are lots and lots of tricks the Vectric software can let you do to get better cuts; you're at the start of a fun adventure. Keep scrap material on hand to try practice cuts at the F&S you're trying to use.

Oh...one other thing...the "speed" part, the router RPMs, has to be set manually before you start the cutting, so be careful if you save multiple toolpaths (that need different RPM speeds) to a single tap/GCode file, because in most cases there won't be any opportunity to adjust the speed between them.

Hope that helps, and welcome to the adventure!

Regards,

Thom

[Keith Hodges]

Thanks for the info guys, I've been using my own HD for a few years now, so I'm familiar with the software. Their is no FRO slider on the Piranah, as with the larger machines control panel on our computers. The Piranah uses a small touch screen. Good info on the feeds and speeds, but I'm looking for something along the lines of the FRO speed control so you can control the speeds at various locations on a project. I'm talking about when your cutting, not jogging. The speed is just too fast.

[Rando]

Sorry man, I wondered whether you might already know all that .

Looks like from the manual, if you click on the X, Y or Z value in the panel, it will let you enter a value and it can move there. So, if you're off by -0.5X and +2.0Y, you'd go into each and enter the opposite values (+0.5 and -2.0), and tell it to go home. Sounds Painful, but that seems to be what they're expecting you to do.

And yeah, I'm seeing no other speed controls that might be available during a run. And, if a USB stick can go into it, that means it's acting as a USB host, not like a device. So it's not likely there is any computer-running control panel that could get you there...without a special A-to-A USB cable. NWA doesn't list one as an accessory, so I'm guessing it doesn't exist, and it won't run from the computer. Bumersky!

Hope that helps (a lot more than the stuff you already knew ).

Thom

[Keith Hodges]

It'll run from a computer, or memory stick, for the files only, or the best I can figure out. I'm thinking that adjusting the feeds in the tool database is the only way to go. Anything I find out at this point will just be transferred to my brother in law for him to try since I've returned home. I got him up and running, with lots of exposure to its abilities, so it's his learning experience now. All in all its a pretty nice "little" machine. Only 12 x 13 inch area of cutting if my memory is correct. Not very big, but you get what you pay for, bigger machines, more bells and whistles.