Laser vs CNC router

[Doug Griffith]

I've heard quite often that if there was a choice between the 2, the money maker from the get go is a CNC router. I can see the point if it's regarding job requests but CNC routers are completely different animals. They have at least twice the steps from design to part, require expensive software, and have an overly steep learning curve. They are nowhere near as easy as using lasers. Doing actual money paying work would be many months behind the laser. I'm not even sure everybody has the capacity or patience to program CNCs. Anybody can run a laser... Well almost.

Laser:
1) draw illustration in Corel, Illustrator or other vector program
2) print to the print driver
3) set power/speed/frequency/resolution and a few other settings
4) focus lens to material height
5) watch the laser do it's magic

CNC router:
1) draw illustration in CAD program or import from other vector program
2) open drawing in a CAM program and create tool paths accounting for cutter diameter, cut depths, directions, speeds, etc...
3) post process to g-code
4) edit g-code for machine specific parameters
5) back plot to visualize and debug cutting process
6) repeat #2-#5 until satisfied
7) load g-code into CNC
8) clamp material down
9) set cutter to surface of material
10) run CNC and cross fingers

The above CNC process was overly condensed and doesn't even take into account machine settings, fixturing, part cleanup, etc...

I know others here use both and am curious if I'm on or off track.

Cheers,
Doug

[Scott Shepherd]

Doug, have you been around CNC's lately, I mean the new ones they are marketing to people who would buy a laser as opposed to the metal cutting ones used by machine shops?

No G-Code, no need to do any of that. Draw it, tell it the end mill size, set your Z, click an icon for cutter direction, and hit go.

It's very very easy. I programmed CNC machines for many years. Manually and with CAM programs, high end CAM programs. When I look at what it takes now, it's night and day.

I think the advantage to CNC machines like ShopBots are that they are inexpensive. For $15,000, you can have a nice one. You can land a couple of jobs, which don't tend to be in the $10 range, and you are done, it's paid for. It's not uncommon at all to get a job that completely pays for the machine itself.

For instance, take Corian signs. If you can get an order for a new building, you can easily pay for the machine in one job. I think that's the logic that you'll hear. I know it's not that easy and it's a bit more like lasers, where I have a feeling there are 100's of people with these CNC machines who can't figure out how to make any money with them.

[Doug Griffith]

I know there are good paying jobs out there for CNCs but am still questioning the software side and setup. Especially when compared to lasers.

I also think I'm up to date with CNC software and haven't seen any draw and cut software that doesn't involve many more steps. I use MasterCam X and SurfCam on a modern MultiCam router. I've demo'd Cadlink, Enroute and Punch products and none have everything. So far, the best tools I've found are cut2D/3D from Punch but all they do is post process.

The only CNC that is even remotely easy to use is the Carvewright but I consider it a toy for hobbyists.

[Dave Johnson29]

CNC router:
1) draw illustration in CAD program or import from other vector program
2) open drawing in a CAM program and create tool paths accounting for cutter diameter, cut depths, directions, speeds, etc...
3) post process to g-code
4) edit g-code for machine specific parameters
5) back plot to visualize and debug cutting process
6) repeat #2-#5 until satisfied
7) load g-code into CNC
8) clamp material down
9) set cutter to surface of material
10) run CNC and cross fingers

Doug,

I have a few CNC machines, lathes and mills and I have separate setup files for the GCode for each machine.

Your #1 through #7 is done in the CAD/CAM software and is fairly integrated and automated.

Your #8 you can't get away from.

Your #9 is handled by the Tool Offsets and the machine offsets in the CNC control.

G54 <-- Go to a preset offset 0,0 position in this case I have it set for the vice jaw back left corner. If I use the CNC Rotary I have it set for G55 as the center line and chuck face. I use G56 for the engraving head which is offset from the main spindle. etc

T01 <-- Select Tool #1 from the internal tool table which will have diameter, length, rotation direction etc etc.

Actually the above two lines are auto-inserted into a new GCode file back in #2 according to the setup file specific to that machine.

We have come a long way baby!

If it comes down to it, I would rather learn a CAD program than Corel. Corel has about 10,000 functions to choose from and requires creativity. On the other hand CAD requires a methodical approach with about 300 commands max.

[Doug Griffith]

Doug,

I have a few CNC machines, lathes and mills and I have separate setup files for the GCode for each machine.

Your #1 through #7 is done in the CAD/CAM software and is fairly integrated and automated.

Your #8 you can't get away from.

Your #9 is handled by the Tool Offsets and the machine offsets in the CNC control.

G54 <-- Go to a preset offset 0,0 position in this case I have it set for the vice jaw back left corner. If I use the CNC Rotary I have it set for G55 as the center line and chuck face. I use G56 for the engraving head which is offset from the main spindle. etc

T01 <-- Select Tool #1 from the internal tool table which will have diameter, length, rotation direction etc etc.

Actually the above two lines are auto-inserted into a new GCode file back in #2 according to the setup file specific to that machine.

We have come a long way baby!

If it comes down to it, I would rather learn a CAD program than Corel. Corel has about 10,000 functions to choose from and requires creativity. On the other hand CAD requires a methodical approach with about 300 commands max.

I don't like Corel at all and see why you'd rather learn a CAD program. Though they are usually bloated as well.

If you started from scratch with no knowledge of either, do you think you would be up and running with a CNC router quicker than a laser? I personally don't think so. Just knowing how to create efficient, working fixtures takes time to learn.

I personally like G92 for setting up arrays of items. I set soft homes between multiple lines of code.

[Scott Shepherd]

Doug, I'm not familiar with those CNC programs, but I can tell you I have stood right behind Ed Lang when it was cutting stuff for me. We imported a shape from Corel, click on the cutter, entered which side of the line to cut on (clicked an icon), entered a feed rate, and hit go. It simulated it on the screen, looked right, hit go, it ran it on the machine.

No G Code, no nothing. I never saw any code, never saw anything remotely related to the old days of CNC. It was very point and clicky.

I agree 100% with you, a laser is so much easier to start off with. Especially if you don't come from the machining world.

I think Ed was using Aspire when I watched him.

[Larry Bratton]

My process is:
Create in Corel Draw or Enroute 3plus
Export to Enroute 3plus as an Ai or Dxf (unless your already creating it there)
Let Enroute create the toolpaths, set the depth of cut, speed and feed.
Export to machine via the Post Processor
Run the file.
(material has to be held down by various methods but that's not related to this per se, their are also material issues with a laser that have to be dealt with)
Not much more complicated than the laser. Granted, the software is more, but today many packages include it.
The first CNC router I looked at in person, I bought. I brought it home, and literally was making and running tool paths within 48 hours. That was 5 years ago and I am still running the same software and machine.

The most difficult part of either one is the software. I can guarantee you that anybody that possesses any degree of competent graphics software experience can run Enroute software. Corel Draw has a much steeper learning curve. It also sounds like that the software that comes with the Chinese lasers is not much better either.

Anddd as Scott said..I defy you to cut designs for signs like Keith or some of us makes out of 1/2" Corian or solid surface for the same investment with a laser. My 40watt will not cut 1/2" solid surface. Quarter is slowwww. I can zip through 1/2" at 200 inches a minute no sweat. I can cut out a design in a matter of seconds and not many minutes.

[bob pfohler]

I have both machines, a ShopBot CNC and a Universal Laser and the CNC is every bit as easy as the laser.

The software for design for the CNC can be Corel or an inexpensive cad program that saves or exports files in a DXF format. My TurboCad was only $99.

My machining software (CAM) for the CNC was $500 and it's very simple and similar to vector cutting with the laser.

In my opinion there are 2 major differences in the machines and the product produced on them.

1.With the CNC one of the most widely discussed challenges is hold-downs. The expensive machines (50k+) have vacuum tables that make life easy. Most of use clamps, screw or whatever stops the material from flying off the table.

2. But the biggest difference to me, as a sign maker, is the work required before and after machining. Laser items can be masked and hit with a can of spray paint. Add some double stick tape or put a screw in the wall and your sign is hanging
CNC items have to be primedx2, paintedx2, machined, sanded, sealed and the letters and carvings hand painted. Also, most of our CNC signs are outdoor installs and we have decide on post or hanging methods.

[Larry Bratton]

Bob:
You should try Corian or other solid surface material for signs in case you haven't. No priming required. Lasts forever inside and 30 years plus outside. It also laser engraves beautifully.

[Rodne Gold]

I have quite a few of both -- 6 lasers and 5 CnCs ranging from engravers on steriods to a fairly sophisticated Tekcel.
For a novice ... the laser is about 500% easier to use - you need have no tool knowledge , machining knowledge , speed and feed knowledge , technical drawing knowledge etc.
Lasers are basically printers. My wife could easily run my laser but I need a "machinist" to run my CnC's.
CnC's only really make money on production jobs and you really only make money as a "wholesaler" to signage co's etc.
At any rate , both are different tools suitable for different purposes and the overlap abilities of both isn't huge at all...We find that having both machines is far greater than the sum of the 2 - IE the results of using both are the REAL way to making good money.

[Keith Outten]

I agree with Rodney that the two machines compliment each other in a big way. If I had to choose between the two my laser engraver would be long gone. My CNC router is the most profitable machine in my shop, easily ten times the income capacity of my laser engraver but that is probably because my target market is commercial signs.

CNC Routers have gotten much easier to operate due to the software that is available these days. Even an old dog can learn a few new tricks with the software that Vectric produces for a long list of machines. The new Aspire software provides a much easier means of doing two and a half and 3D designs, something I never figured I would be able to learn to do in my shop.

As Larry mentioned above Corian is an absolutely magic material for engraving and for CNC routing. Corian is versatile and very forgiving with little cleanup to do after routing, sharp bits will leave an almost polished machined surface.

[bob pfohler]

Bob:
You should try Corian or other solid surface material for signs in case you haven't. No priming required. Lasts forever inside and 30 years plus outside. It also laser engraves beautifully.

I do use it for small indoor signs but large (4"x6") outdoor signs it's very heavy and expensive.

[Doug Griffith]

For a novice ... the laser is about 500% easier to use - you need have no tool knowledge , machining knowledge , speed and feed knowledge , technical drawing knowledge etc.
Lasers are basically printers. My wife could easily run my laser but I need a "machinist" to run my CnC's

Exactly what I think!!!

I know there's sign software out there (ie. Enroute, Aspire, VCarve...) that makes it easier than the process I go through but a CNC programmer/operator still needs to know what he's doing. If he "screws up" while setting up a laser job, the worst that can happen is ruined material or, if he's careless, a fire. A CNC can do some SERIOUS damage if the head crashes. Plus it's dangerous.

I think if 2 people with no related knowledge were given everything they needed to do both processes, the one with the laser would be producing items far quicker. The one with the CNC would still be figuring out how to hold the material down.

[Scott Shepherd]

I agree with you Doug, the laser is far easier. One thing I see missing from so much of the router world is hold down. I've machined more parts than I could ever count (so, that's roughly more than 3), and never once did we ever hold anything down with a vacuum. It was attempted a time or two, but at no time was vacuum considered a viable workholding device while using endmills or carbide cutters.

However, that seems to be the battle cry of how you should hold things down. In my experience, you had a clamp or some mechanical method of holding the work. More often then not, when chips got back into the cut or a piece of extra material that's getting milled away comes back into the cut, it either sucks the scrap into the cut, between the workpiece and the cutter and spits it out the other end, or it breaks the cutter. You work doesn't move. However, with the vacuum systems I've seen, if it chokes on chips or a scrap of material, then it moves the workpiece.

If I had a CNC, I'd be a clamp guy, not much of a vacuum guy on the hold downs. But that's just my opinion.

[Rodne Gold]

We hold everything down with either vacuum or mainly double sided tape..We use a double sided tape that strips off cleanly.
If you use the correct bit and speed and feed , there shoud be little or no lateral force on the workpiece. We often cut with "bridges" , teeny little tabs that hold the cut piece in place on the sheet of material and break the cut piece out after - works real well and most packages do em automatically. Vacuum holddown is very strong but requires some serious pumps , for our one 4ft x 4ft table we have a 7.5 hp pump and still have the ability to blank areas. I use a thin sacrificial mdf sheet on the table proper - we drill it and mill channels and the suction is strong enough to go thru the mdf itsself...I must say , the double sided tape is a lot easier - we put a bed of 10mm thick pex on our 4 x 8 tekcel and mill it flat and stick the stuff on it.
I seldom do anything that requires clamps , but 2 of our tables are T slotted to accept clamping fixtures when we need to do it.
Essentially our CnC machines are computerised routers , not true CnC mills like a Haas.
the software can be as expensiveas a machine , I use mastercam , signlab, profilelab and artcam and shudder to think what those packages cost me.