What CNC machine would work best?

[James Leonard]

Hi, look at what is being done on the CNCZone with bolt-together tables made from 8020 aluminum extrusions. With a Gecko G540 electronics kit you could build a table for the low end of your cost range. Since you would want two spindles, that is the real issue in your design. I'm not sure woodworking routers would process aluminum well on a production basis. One of your spindles would be a drill (maybe). Since this is for a special purpose, maybe you could use plunge cutting endmills of the size needed for your hols to cut your profiles also. Then, no tool changes and no second spindle.

-James

[Bryan Cowan]

Hi, look at what is being done on the CNCZone with bolt-together tables made from 8020 aluminum extrusions. With a Gecko G540 electronics kit you could build a table for the low end of your cost range. Since you would want two spindles, that is the real issue in your design. I'm not sure woodworking routers would process aluminum well on a production basis. One of your spindles would be a drill (maybe). Since this is for a special purpose, maybe you could use plunge cutting endmills of the size needed for your hols to cut your profiles also. Then, no tool changes and no second spindle.

-James

All holes are 1/4" in diameter. Seems as if I use the same tool to cut out plates, there would be a lot of scrap.

Would it be possible to have one spindle, drill the holes and once they are complete, change tools and go over the sheet cutting out the profiles? That's how I pictured it to work.

As far as "production basis", I'm not quite there yet. If it saved me considerable time by removing the bandsaw, vertical sanding belt, center punching, and the drill press, I wouldn't need to use the machine on a daily basis. I may use it for an hour or two everyday. The time saved from other manual processes can be spent with my wife...if she read this, she'd love that

I also don't want to limit myself completely. While I may only use it for aluminum, my brother-in-law may use it for woodworking...I'd at least like to leave that option open.

Cost certainly is an issue, as with everything else, but I also don't want to fall into the category "You get what you pay for"

[james mcgrew]

yes my first machine had one spindle and all i had to do was change bits and reset my z0 each time, it is not a difficult process. oh and the wife well i got that one too!!

jim

[Rob Slaughterbeck]

I can certainly appreciate the desire for a CNC, but for the tasks described, it is definitely WAY overkill. A few well made jigs will go a long way in producing clean cuts and reducing production time. I just finished making a drill press jig for a buddy to drill 6 holes in 3/8" aluminium and steel. It holds all four pieces of his assembly together so he can drill all the pieces at once and ensure the holes all line up. Whereas before he was having to mark, punch, and drill 12 holes with a cordless drill.

CNC's are great machines at producing complex shapes or one-off items. They can also be slower and more expensive at automating simpler tasks. I'd be interested in looking at your plans or parts to have a better idea of what you are trying to accomplish. Another option to consider is a hydraulic punch/press and metal shear.

Rob

[Bryan Cowan]

I can certainly appreciate the desire for a CNC, but for the tasks described, it is definitely WAY overkill. A few well made jigs will go a long way in producing clean cuts and reducing production time. I just finished making a drill press jig for a buddy to drill 6 holes in 3/8" aluminium and steel. It holds all four pieces of his assembly together so he can drill all the pieces at once and ensure the holes all line up. Whereas before he was having to mark, punch, and drill 12 holes with a cordless drill.

CNC's are great machines at producing complex shapes or one-off items. They can also be slower and more expensive at automating simpler tasks. I'd be interested in looking at your plans or parts to have a better idea of what you are trying to accomplish. Another option to consider is a hydraulic punch/press and metal shear.

Rob

I produce approximately 70 different sizes of plates, and the number of different plates grow monthly with the continual addition of new product. Some plates are more popular than others and thus not every 24" x 24" sheet is cut into all the same plates. With my current bandsaw and the size of the sheets, a jig isn't possible.

A jig would work with the drill press; however, that process is the least of my concerns. The tolerances on the 1/4" diameter holes are large enough for a little variation and being 1/8" thick, it doesn't take much to drill through.

I began thinking about a CNC because I believe a CNC could possibly eliminate all my current manual labor:
1. I will no longer have to trace outlines of my plates on the aluminum using a marker.
2. I will no longer have to hold and balance the aluminum on the small bandsaw table while feeding it through the bandsaw. 80% of the time I'm straight, the other 20% I get a little crooked. Having crooked cuts doesn't ruin the product, but it loses it's visual appeal.
3. I absolutely hate bandsaw tooth marks.
4. I will no longer need to de-burr the plates against the sanding belt that the bandsaw created. Some of my plates have a radius so I cut them as best I can on the bandsaw and then use the sanding belt to "round" them out...not always perfect.
5. I will no longer need to center punch the plates.
6. I will no longer need to drill the plates with a drill press.

With a CNC (and my little knowledge of it), I believe I can create the program, load the proper tool and aluminum, and watch it go to town. I would imagine the CNC machine would make the processes quicker, but even if its slightly slower, I'll know plate 1 will be identical to plate 1000 and not look "home made". In addition, while the CNC is doing the work, I can work on other business related tasks, therefore being able to spend more time with my wife in the end.

Thanks Rob, you definitely made me think about the entire process and I really think this would be good for me. I could always outsource my work, but after awhile, the money I spent on that could have been used to purchase my own machine. Business is picking up, since 2006 business has grown 300% and the only thing holding me back from continually growing is the lack of time I have because I spend most of it on manual labor.

I will continue to do my research and listen to all the feedback I receive before taking the plunge. I want to make sure I make the right decision the first time around.

Thanks again,
Bryan

[Bryan Cowan]

Before purchasing a machine, what software is available that I can "practice" on? By practice, I mean writing the G-code, setting the speed/feed settings, and then simulating the machining to determine process times.

Thanks

[Steve knight]

to cut aluminum you need a better then low end machine. even then the cut will not be super smooth. plus it is pretty slow. you can't take much off in a pass.
getting someone to make you jigs on a cnc and investing in metal working tools would be the way to go. a metal cutting bandsaw like so
http://www.grizzly.com/outlet/Vertic...-Bandsaw/G0621
use a template to guide it. then use a table router with a flush bit for the final work.
it would be faster then doing it on a cnc machine.

[Keith Outten]

Bryan,

Visit the Vectric web site, you can download VCarve Pro (2D) or Aspire (3D) software and try it out for free. Forget having to write G-code, modern software has removed that burden.

Steve,

I can't imagine a situation on a production job where manual routing would be faster over an eight hour period. Even if i could hand route a part faster then a CNC I can't hold a router in my hands eight hours per day. As already stated above a CNC machine allows the operator to work on other things while the router is running thus another job function can be implemented simultaneously.

Without specific details I guess we are shooting in the dark here but its brainstorming none the less.
.

[james mcgrew]

www.vectric.com will allow full demos of all of its software, try vcarvepro and do not let the name fool you, while it is not parametric it has yet to not do any thing i have needed. full demo files can be run on your machine prior to purchase. as far as aluminum with the right "0" flute bits, feed speeds and coolants it will cut with some amazing property on many different machines. if the current method is with a sharpie then the accuracy will amaze you!! all of the parts on these machines (1",3/4", 1/2") are cut on the same machines

jim

http://www.youtube.com/watch?v=v2DRltiqAw0

[Bryan Cowan]

Steve,

The aluminum is no more than 1/8" thick and is 6061/6063 grade; very good machinability. If the hobbyist/bench top tools I'm using now can do the job, I would hope a low-end CNC could as well. Also, I'm trying to remove the human element as much as I can without breaking the bank. Of course there are other manual methods of what I am currently doing, but I believe that will only have me move sideways rather than forwards. While I would like the CNC to speed up processes, I won't be heart broken if it doesn't. If it provides consistent parts with a better finish AND removes me from all the manual labor I'm currently doing, I'll accept slower times.

Slightly off-topic, at my day job, we used to roll stamp our metal parts with our logo and part number one piece at a time. With a competent operator, they could knock out 100 pieces in 8 minutes. Trying to improve processes, we brought in an Epilog FiberMark laser system that will mark all 100 pieces at once, completely removing the operator and freeing them up to perform other duties, but also slowing down the process. Those same 100 pieces now take 20-30 minutes to complete. We accept the slower time because of the consistent results from the laser as well as the time is frees up for the operator. With the roll stamper, 100 pieces took 8 minutes for the machine and 8 minutes for the operator (16 minutes combined). With the laser, it's 20-30 minutes for the machine which then freed up the 8 minutes the operator used to spend stamping the parts. Theoretically, the laser only takes 12-22 minutes for 100 pieces...Understand my reasoning? So while the process isn't faster, it does improve other aspects of production. Now, if my manual labor now of 2 minutes per part skyrockets to 10 minutes per part, maybe this isn't the way to go. That's why I want to play with some simulation software to determine the end results.

Keith,

Thanks, I will look into those programs. As I said in my first post, the only CNC experience I've had is with G-code for a semester many moons ago. I'm open to new technology

And yes, we are brainstorming and it's great. I value everyone's opinion and thoughts on what I'd like to accomplish. It allows me to think about everything without (hopefully) missing any details. It will help me make an informed decision down the road.

Jim,

As always, thanks for your replies and nice video collection on YouTube. After watching a few, I searched YouTube for "camaster aluminum" and came back with this - http://www.youtube.com/watch?v=cjvTUJ1lSPY

Aside from that material being much thicker than what I'm going to use, that is exactly what I need this machine to do. It drilled the holes and then routed out the shape -- PERFECT!

[Robert Alexander]

Steve,

If the hobbyist/bench top tools I'm using now can do the job, I would hope a low-end CNC could as well. Also, I'm trying to remove the human element as much as I can without breaking the bank.!

Bryan If you have the skills and want to save some money look at building a MecMate router. It will cost $4000 to $5000 to build. I am looking in to building one in the near future.

[Bryan Cowan]

Bryan If you have the skills and want to save some money look at building a MecMate router. It will cost $4000 to $5000 to build. I am looking in to building one in the near future.

While I consider myself handy, I also appreciate the out-of-box product and don't mind spending the extra $$ on knowing what I bought is going to work and the tech. support behind it when it doesn't.

[Steve knight]

I have cut aluminum on my shopbot. but it is slow and messy and only looks ok. you only take about a .03" deep pass at about 1 to 1.5 inches per second. that's about 8 passes to cut it.
even though I do so many things on my cnc router sometimes other methods are faster. rounding over I can do far faster on a router table.
cutting stock in basic shape is faster on a tablesaw. cutting aluminum is faster on a decent saw.
a small cnc machine will not do well with aluminum. without a spindle rpms will be very fast and cause issues.
the best tool is a cnc mill. it would be faster more accurate quieter and cost less to run. plus the edges would be far nicer too right off the machine.

[Bryan Cowan]

the best tool is a cnc mill. it would be faster more accurate quieter and cost less to run. plus the edges would be far nicer too right off the machine.

Steve,

Being new to this entire venture, can you suggest any CNC mill companies that may accommodate hobbyists/small businesses?

I'm not going to limit myself to a CNC router; if it's not the best tool for my needs, then I need to know that and move on. So I appreciate you taking the time to explain all this to me.

Thanks,
Bryan

[Bryan Cowan]

What's the difference between a CNC router and CNC mill?
With the router, the work piece stays in one position and the tool moves. With a mill, does the tool stay in one position and the work piece moves?