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Buying a CNC CAD

longryde

Plastic
Joined
Nov 20, 2005
Location
Minnesota
Hello-

I am in the thermoforming business. (30 years) I am going to bring tool making (molds) inside my business. The cost of having my molds made has become to frustrating and prohibitive.

I would only have to make 1 to 2 molds a year. I have never worked a cnc machine before, but learn quickly. I am very good with computers.

My biggest mold I would have to make is 19 x 27 and 6 inches deep. The smallest being around 7 inches round.

The molds are simple convex circle and rectangle shaps. Some of which i may be able to to use Ren-shape for short runs, but aluminum for long runs. The material I am shaping is very thin guage (18-20 mil) PET sheet.

I am curently looking at a SHOBOT with a 5 hp columbo spindle and a 1996 HAAS. The Shopbot is more interesting because of everything it can do.

Any advice?

Bill
 
edgecam or mastercam.
try them both before you buy. they are on my hub
 
Hi Bill,

Maybe you are using the wrong shop to make your molds?

The cost of having my molds made has become to frustrating and prohibitive.

I would only have to make 1 to 2 molds a year.
To me something doesn't quite add up. If these mold are like simple Vacuumform molds it would be a number of years before you hit break even on cash outlay, not including learning curve.Now if you just want to gain control over you entire process, thats another story. The small mold with simple shape should cost a couple hundred bucks. ( And, no, I am not soliciting buisness. Swamped till well into next year. ;) )
 
I am sorry, forgive my typing. SHOPBOT is the correct spelling.

I recently had a a quote done for a 19x27 inch - 6 inch deep convex mold. basically a bucket in aluminum. $20,000 dollars. That was it for me.

I can buy a number of machines for that, my learning curve is free - since I work for myself and time is not an issue. I also feel confident in my ability to learn how to do this.

Bringing this "in house" would give me more creative ability - being able to experiment with different shapes and sizes any time I wish.

I will research edgecam and mastercam.

Thank you for your assistance.

Bill
 
I want to point out that I am looking more for the CNC machine itself. If someone could offer me practical advice on a good entry level machine for my objectives. I am curently looking at Rhino 3d software, to design my tools. This again could easily interface with a SHOBOT. I would not need rocket science software to create my designs.

My business and products can be see at www.seeacake.com to give you a clear definition of the tools I would be creating.

Thanks

Bill
 
I just bought a Haas. I may be a little biased. The best bang for the buck I think is a Haas. If you are going to be making a couple of molds a year, I'd find a used one and buy a copy of Mastercam and MAYBE a copy of solidworks.
That would take care of all your mold work
Jim
 
Thanks- There seem to be an endless number of HAAS and Fadell machines available. EBAY and Reliable Tools seem to offer many choices of either name brand.

I will continue researching - any adice is welcome.

Bill
 
The only ShopBot I see is a router? That is definitely not a mold making machine if your mold is more than an inch deep.

Haas VF3, mmm, ya :D

Check out OneCNCXR2 before buying modelling or cam software. For someone who might be using the software infrequently, you want something that is easy to learn and easy to remember how to use. You won't see this software on Pi's hub, and what he shows you as 'Onecnc' is now 4 generations old.
 
Bill,

The ShopBot machines could be ruled out immediately. Their construction is far too flimsy to ever allow any serious machining, even on aluminum. While it would be possible to eventually end up with a mold via nibbling and gnawing with a shopbot or similar machine, the lack of rigidity would leave you with surface finishes requiring more hours of polishing and handwork than any sane human would ever want to spend on such a fun task :D

What you're wanting to do can be done by any number of vertical machining centers. In looking for a used machine, past the obvious mechanical health and operating condition, there are two major criteria I'd look for.

First, get a fully enclosed machine. Its essentially impossible to keep the chips or coolant contained within anything less, particularly when cutting aluminum, due to the high spindle speeds and high coolant volumes necessary to keep the cut clear of chips so that the best surface finish can be maintained. I've cut some similar parts on an open cnc mill, and for the entire duration you have a fulltime job with a mop and a broom in trying to keep the mess contained. It gets old, real fast.

Second, you need a control with adequate block processing speed to be able to run a typical mold cam program without starving for data. Mold programs are typically made up of thousands, or even hundreds of thousands, of short linear moves, and a lot of older controls are incapable of processing the lines of code fast enough to maintain constant feedrates. Every place where the axis motion stops due to data starvation will leave a place in your mold that can easily be seen and felt, leading to lots of hand finishing work that wouldn't be required with an adequately fast control. You can't get around this situation by slowing the feed to allow the control to keep up, because all that will happen is that the general finish will go to hell, along with your tool life, due to inadequate feedrates.

There would be several dozen different brands and models of machining centers in the used market that would meet the above requirements, so you have plenty of options on what machine would do the job.

Its my opinion that you should think about getting more quotes for your work before making a final decision to buy a mill. Going under the assumption that this is a relatively low tolerance mold where surface finish is the main objective, and that it doesn't have a lot of features you haven't mentioned, such as a bunch of gun-drilled coolant passages, etc., I'd agree the $20K price sounds ridiculous. However, a big drawback to doing it yourself is going to be the question of how rusty your knowledge becomes during the months when your mill sits idle between jobs. I work by myself most of the time and have a lot of different machines. When I start to run a job on one I haven't used in several months, it requires a re-learning time before I'm back up to speed. This is true even with manual machines, but is about ten times more evident with cnc machines. The same would be true with whatever CAM software you choose, and in most instances that re-learning after a long layoff can take lots more time than you'd spend getting back up to speed on the machine itself. Assuming you can furnish a shop that's quoting the job a solid model from Rhino, and assuming the shops quoting the job have CAM software capable of importing and directly processing a solid for generation of the code, I'd have to agree with Ted (smallshop) that something in this picture is way out of line. Shopping for a supplier might pay lots more dividends with lots less headaches than any other option. If a person allowed $2000 for the material for your 19x27 mold, which would be high, that still leaves 4.5 work weeks at $100/hr to make the mold. Seems more than a little steep to me.
 
Thanks for the replies. I did check out onecncxr2, I will call them first thing on Monday.

I have made up my mind on bringing this in house to accomplish my tooling needs, I have become too frustrated on the costs of these simple molds and wasting my time with outrageous quotes.

Although, I have a few mold that I would like to accomplish soon and a mold that is almost completed that still needs a little work. I would appreciate an experienced cnc machinist giving me a call at my office 1-800-854-1920 to dicuss milling these tools for me for a fair and reasonable cost.

Thank you

Bill
 
Pi, I'm curious why your preferance to the VF3
his standard job size is 19x27.
vf3 has a 40" table. this would allow him plenty of clearnce for a vise if he is setup on a mold and needs to make an emergency small job. the smaller 30" tables would be too close for comfort and allow no room to grow. he should also take the same attitude towards software. i dont think onecnc is a wise choice for mold making software.

it's obvious why i dont recommend a fadal
 
Doesn't the VF3 have a 40" by 20" travel? That 19" part with the 20" travel wil be just close....As long as you can rough and finish the outside with a small enough cutter, I guess it fits. Just be aware of it, certainly doable.
Pete
 
If you are going to use Rhino (excellent choice!) for design, why not buy RhinoCam and get cad and cam in one package. RhinoCam is VisualMill running native in Rhino. Which is a good marriage. VM is a bit light on drawing tools but CAM's nice. If your molds are very free form you will love Rhino. That 20k mold sounds like an easy weeks work.3K-5K if my understanding of the mold is somewhat correct. A buddy of mine borrowed my machine to to do an Alum. vacuumform mold that was 24" long, 6" wide and about 8" deep. I think he charged $1600.00. Just pointing out the money you may be saving by doing it yourself may not be that big a saving if you had the right shop doing the work. With the roughing routines and finish routines on most cam programs 3D work is easier and faster to program than stuff with a lot of steps and pockets and details.Have you priced many shops in your area for your work?
 
Just curious about one thing. Are your molds typically a male plug or a female impression of the part? Not a question that makes any difference within this thread, but rather something I'd like to know.
 
I will have say that I have not shopped the job out thoroughly. I would actually be happy to pay the amounts you have indicated for these molds.

I still enjoy the idea of learning this trade and milling my own out. It would be a great find to have a reasonable mill operator with enough interest in my business to assist in the creative side of the mold.

I have several molds on mind for creation. 2 of them I already have designed but need deeper molds for a double layer cake. I also need a new design for a log roll 12" by 5" by 5" deep.
All of my molds are convex tools.

Thank you again for your advice. It is much appreciated.

Bill
 
Bill
take a look at milltronics, has some 3d routines on the controller, sweeps, tapered walls, cavitys, cores ect (CENTURION 6). mine (5 years old) has good look ahead and bps.(mold package) i do injection molds, run large electrode programs(5-6 meg)with little problems, run form a now obsolete 120 meg super drive on controler, will start dnc via wire soon.
rk
 








 
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