cutting sign blanks

[plimandri]

Hello everyone,

I'm sure this is pretty elementary to most however I am not sure how to cut sign blanks without tearing up the table on the shopbot buddy I have.

Can someone let me know where I can get directions on properly cutting sign blanks on the machine please? I used to get the pre cut signs however the supplier is no longer providing them at this point.

Thanks for your help

Phil

[bleeth]

Phil: That's why the top layer of mdf is called a "spoilboard" You cut parts out a small bit deeper than the thickness of your material. To damage your spoilboard the least you can leave a skin and cut parts out with a trim router. If you cut through and have no vacuum then you use tabs in your design. If you need help on tabs and can't locate it in the software instructions make sure you tell us what software you are using.

[CNYDWW]

There are several things you can do. First, Apply another spoil board on top of the table. Another option would be if you use mechanical clamps. Use inexpensive 1/8" or 3/16" masonite or hardboard under your material. It would get the abuse from cutting through. Still another option is using a flush trim bit on a regular router or laminate trimmer with the bearing on the shank side of the cutters and leaving a skin at the bottom of your cuts. Same dia. as the cutting bit you use would work perfectly.

Just a few of many options.

Regards
Randy

[plimandri]

Thanks to you both I will start experimenting with this tomorrow. I truly appreciate your help.

Phil

[ssflyer]

Hi Phil,

To elaborate on the suggestions already given, here's what I do (and the only marks on my spoilboard are from my own mistakes :D)

When I'm cutting through, I always Z-Zero to the table, not the material top. That way, no matter what variations your material may have, the 'bot knows where the spoilboard is. Then, on my profile cut, I leave between 0.001 -0.003" of material, and use a downcut bit - this leaves the sawdust/chips in the cut and aids in keeping it in place.

With such a thin skin left, it can be easily cut out with an X-Acto knife. Unless the piece is very intricate, I usually don't even use tabs with this technique.

Hope this helps,
Ron

[blackhawk]

A lot of times I do something similar to Ron. I leave a thicker onion skin of say .06 to .08" thick. I then take the part over to my workbench and lay it upside down. I then use a 1/4" diameter flush trim bit to cut it free. I put a link below to where I bought my flush trim bit. Of course, the flush trim bit won't cut in a tight radius that is less that that of the bit.

http://www.rockler.com/product.cfm?page=11322

[signtist]

I almost always use a sheet of coraplast under my work. Just toss it out when it gets cut up too much. John
www.signgraphics1.com (http://www.signgraphics1.com)

[joe]

I'm more like Prof. Arnold. To heck with the oinion skin and saving the spoil board. I let her rip plumb through. When the creative juices are flowing it's kind of slash and burn. One of the most aggrivating problems for me is when my panel and details are not cut all the way through. The second pass around is a waste of time. Double down so and get on with the project. You have to pick your personal ways of running a shop. Since I don't have a vacuum hold down or many fancy manual hold clamps and since I don't carv little thin stock, I'm best replacing a spoil board every month or two.

Isn't this forum great. We have lots of different approaches. But, when you start out, don't get hung-up on any one way. Just dig in and see what happens.

Joe
www.normansignco.com (http://www.normansignco.com)

[signtist]

Someone asked me once......"What if you mess up"?:eek: I just laughed!

[curtiss]

I usually use a climb spiral cut for final cuts. It cuts slowly deeper though-out the cut.

If you make a small curve (say .1 radius) on the corners they seem to chip out less.

I usually set the final cut to 1.000 inches. If the stock is only .75, I adjust the depth to say .800 at the z proportion right before the file starts.

[tuck]

Interesting about spoil boards. I agree with Master Joe, "cut through and then some!" Nothing is more frustrating than finding out you didn't cut all the way through, especially when you're cutting a lot of parts!

John, I'll have to take your word that coraplast works well although I can't imagine a sheet would last very long on a busy machine. MDF is the material of choice for most of us for spoil boards but it has it's problems too. It "pooges up" when cut and requires more attention than it deserves.

I think the ultimate spoil board for those of us that don't have a vacuum table would be 1.5" (or thicker) HDU mounted on top of some MDF. Yes, it's expensive, but it's stiff, can be easily milled and planned, and a one sheet could last many times longer than a sheet of 3/4" MDF, which is about $40.00 these days. It doesn't "pooge" or move, is dang near impervious to temperature changes, doesn't care if it gets wet for any reason, and holds screws good enough.

I can't afford to experiment with my idea, so if anyone does try it, let us know how it worked out! ;)

[joe]

My next door neighbors have BIG IRON and they cut onion skins all day long. They send the creative work my way. If your engaged in creative routing, you've gotta break the rules and be ready to make mistakes. I love creative mistakes. I make them all the time. Sometiems they lead me in new directions which define my business.

HDU as a spoil board sounds like a good idea because it's stable but it's not good with screws. Every thing I route is held down with bolts and screws. I'd use some 1" MDF except my back hurts thinking about it.

Joe Crumley
www.normansignco.com (http://www.normansignco.com)