cutting 4 by 8 router

[angel_skull_crusher]

Hey guys,

Someone just asked me to cut out a design. This is my first job, so I think I am going to mess it up as they say. I have ten pieces of plywood to cut and the thickness is 0.75 and they are 4'by 8'. The pieces are basically plywood with little designs for a logo or a sign. I think they are pretty good. I am going with the 1/4 inch end mill bit, 24000 rpm, 90 IPM, and plunge of 30 IPM with depth of 0.125 per pass. It is going to take 22 hours to cut this but my shop only lets me use the router for 2 hour blocks.

I need to figure out how to get more time on the router in one continuous day long block. Ideas?

Steve

[Leo]

I don't know the capabilities of the machine you are using, so this may be impractical.

I just bought a Chinese router and I ran some test cuts on a Walnut slab I am facing for a coffee table. I used a 1/2 carbide tipped straight flute router bit (NOT - the best tool selection) and ran it at 500 IPM, cutting at 1/4 deep. It cut flawlessly. I could have gone much faster.

If you can increase your feedrate while still maintaining a decent chipload, you will dramatically reduce your cut time.

[ger21]

With a 1/4" spiral router bit, try 1/4" per pass, 350-400ipm, and 18,000 rpm. Your bit will last a lot longer, and you'll get done a lot sooner.

Never plunge. Ramp in at 200ipm or more.

[Ms Wolffie]

Is there a chance they will let you use the machine in the weekend?
Then you can save up your 2 hour blocks and do some work for them in those 2 hours.

[angel_skull_crusher]

1/2 in at 500IPM and what RPM? That Chinese machine is running a scramjet or rocket powered end mill. I was hoping to add a conveyer belt to my CNC for high throughput manufacturing.

[Leo]

1/2 in at 500IPM and what RPM? That Chinese machine is running a scramjet or rocket powered end mill. I was hoping to add a conveyer belt to my CNC for high throughput manufacturing.

About 15,000 RPM

[angel_skull_crusher]

I was informed that I only have one 4 by 8 piece to cut so my time is now about two hours. I have to set up the piece and install it on the router. I also have to load it onto the truck or whatever transport there is. I think it would be fun to load the piece onto the router without having to do any other transfers i.e. directly from truck.

S

[martin54]

It shouldn't take to much time to get set up, an 8 x 4 sheet of 3/4" ply is manageable enough that you can get it on the machine without to much difficulty & pretty easy to set up square. What sort of hold down do you have? Most likely Vacuum hold down from the little I know about Laguna CNC's.
If it's not vac hold down & you intend to use some sort of screw to mount to spoilboard then when you set up your material for cutting include the locations of the screws as well,

If your only ever going to get blocks of 2 hours at a time this could cause problems for you in the future especially if you get interested in 3D work where machining can often take many hours.

[Dclifton2]

I'm just wondering how at 400/500 IPM you would get sq corners or accurate cuts?
Don Clifton

[Dclifton2]

Martin, I see you have a Gerber 48, my first two factory machines were Gerber AR400 that I converted to Mach3. I have cut a lot of the plastic gears for my self and other owners.
Don Clifton

[fixtureman]

I'm just wondering how at 400/500 IPM you would get sq corners or accurate cuts?
Don Clifton

I run mine at 350 to 400 cutting .75 ply with a .5 compression bit 1 pass on a Shopbot

[Dclifton2]

Again, how do you cut sq corners going that fast. Mach will round the corners off unless you set the stop CV on angles greater than which slows you down any ways.
Don

[martin54]

Again, how do you cut sq corners going that fast. Mach will round the corners off unless you set the stop CV on angles greater than which slows you down any ways.
Don

Don far as I am aware most control software works in a similar fashion, you have to slow for sharp corners or defy the laws of physics Gantries can be pretty heavy & won't stop dead on a dime- Setting the machine to cut at 400-500 ipm doesn't mean that the machine will actually ever reach those sorts of speeds.
As well as corners you have to take into account how many axis are moving, z axis is normally set slower than x & y so when z axis movements are taking place machine probably won't reach those sort of speeds either.

[angel_skull_crusher]

I think this forum is for a setup of a 4 by 8 board. As for cutting corners, I am not sure if that is some kind of joke. When I was milling with the hand mill in Berkeley, I had to cut tool steel for a hammer head. I used an edge finder and some centering milling tools to get my hammer head accurate to 0.001'' or one thousandth of an inch. I mean for something done by hand. Anyway, the cutting of corners is something that I would do with the CNC because the shape can be programmed. I am considering new parabolas that are just funny ways of making new x and y coordinates in the Cartesian plane.

I hope this makes sense.

S

[martin54]

Apologise if you feel the threads been hijacked, tried to delete my last post but can't seem to either edit or delete it.

No joke about cutting corners, with any CNC router operation there is a trade off between speed & accuracy. Don was asking how people could cut at those speeds and maintain sharp corners.