More Beginner CNC Mill Questions - Please Help!!

[8SECNOTCH]

I am looking for a CNC Capable / Ready to go Mill. My problem is I don't want to buy something that I will out-grow too quickly. I will be machining mostly aluminum parts usually no bigger than 10 x 5 x 1/2-1 thick. Do you feel the Harbor Freight "Mini" will be enough? How long do you think it would take this machine to produce a semi complex part around this size? What are your thoughts on the next size up HF 1-1/2 HP HEAVY DUTY MILLING/DRILLING MACHINE? http://www.harborfreight.com/cpi/cta...emnumber=33686

I went to "Smithy" yesterday (1/2 hr away) to look at what they had to offer as they where supposed to be running a "HUGE" scratch & dent sale however it seemed as nothing but a gimmick to get you in the door. Is anyone familiar with their new CNC 1240 BED MILL? It's $12,999.! - They had the proto model on the floor for-sale for $10,000. It came with just about everything to get started & a "generic" I presume tool pack. This is exactly (capability wise) what I am really looking for - only not the price (I hope) Servo motors, Ball screws, ETC....

PLEASE HELP - LOOKING TO GET UP & RUNNING SOON AND QUITE POSSIBLY PAY SOMEONE TO HAVE A MACHINE CONVERTED / BUILT TO CNC IF I GO THAT ROUTE.

Thanks everyone & look forward to some good discussion - Rob [/COLOR]

[NeoMoses]

Don't be immediately turned off by what I have to say, but listen carefully. You have to ask yourself what your intentions are with a machine like this. If you intend to produce parts for a hobby, you'll probably be fine with a smaller mill. Hobby work usually doesn't care if you have to re-fixture a part 3 or 4 times. If you're trying to make this into a production CNC, be prepared to spend a bit more money. From the tone of your post, I'm assuming you're wanting to use this for production rather than hobby. Correct me if I'm wrong.

One major problem with most of these smaller mills is spindle speed. To be time efficient in aluminum, you need high spindle speeds. 5000+ RPM at least. 30,000 RPM would be nice.

If you're just starting, also ask yourself this: How long can you take to learn how to machine? I'm assuming you're not already a CNC machinist and you've never built a CNC mill before. If you want to build a machine, learn how to use it properly, and get a product to market in less than 4-6 months, you're just dreaming. This is one place where experience is needed.

If you want to get a product to market in a timely manner, have the first few batches machined by professional machinists. Use the profits from these batches to invest in a small prototyping CNC machine for yourself. (Prototyping can be very expensive since each piece is usually unique). Once you become more experinced in the world of CNC machining, you'll be able to determine if you should be the designer AND the manufacturer or just the designer.

I'm speaking from a position of experience. I built a 'small' CNC machine that I thought I could use for production. It took months for me to become productive with it. After looking around, I found that I could get parts made by a professional machinist cheaper than I could make them myself, assuming that my time was worth $5 per hour. It was at this point that I realized I should be the designer and leave the manufacturing to someone else.

Hope it helps. Feel free to let us know more specifics and we can give you better advice.