Retail, Low price CNC

[Joe CNC]

My group and I are currently designing a low cost CNC gantry to fit common rotart style cutting tools (like the dremel type) for our Senior Design class in Mechanical Engineering. We are currently looking at the market and would be ever so grateful if we could get all your input on how this 'thing' should be designed. If you could send any comments on specs or things that are of concern to you (travel speeds, cost, accuracy, etc) to CNC_group@hotmail.com, we would be very grateful.

[CNCadmin]

Read though the threads here their is a wealth of information.

[chuckknigh]

Check out http://***** for some good ideas, too. John Kleinbauer sells plans for machines similar to what you describe, and has quite a few ideas which have been proven to be VERY useful to those of us in this hobby.

I second the idea to just read this woodworking forum...a LOT of us have built machines, successfully, and have posted details of our designs, including analyses of what worked, and what didn't.

Also, while you're here, check out the "Open Source" forum on this site...many of us are participating in a volunteer project to design a set of plans for the newcomer.

-- Chuck Knight

[signIT]

I will stay with the Zoltar CNC router it is enough for most people who makes signs and small parts from all kind of soft metal and plastic material.

The Zoltar design may be improved but not less expensive, if anybody will make a cheaper machine then this design, it must be made of paper and biscuits.

[Joe CNC]

I will stay with the Zoltar CNC router it is enough for most people who makes signs and small parts from all kind of soft metal and plastic material.

The Zoltar design may be improved but not less expensive, if anybody will make a cheaper machine then this design, it must be made of paper and biscuits.

Thank you for your input and your criticism. Even though I agree with the fact that the Zoltar is a cheap design, It is BUILT rather than ENGINEERED, which is what my group is planning on doing. In addition, keep in mind that the whole thing still has to be built by the user and is not offered as a kit/preassembled unit. On top of that our current estimate is that we could hit the market at a cost of about $400-500 based on a current parts price and mark up of x2 (therefore not thorugh wholesale).

I encourage an active discussion on this though seeing as we are in need of input so that we can finalize the specs (we really need your input: CUSTOMER NEEDS!!).
thanks again,
Joe

[High Seas]

It is BUILT rather than ENGINEERED, which is what my group is planning on doing.

EXCELLENT! It would be great if you guys can through the engineering process reach some conclusions regarding the mechanical trade offs. I'm thinking as you enginneet the product, what differences in resolution are achieved - given up by using:
drawer slides
Skate bearings on pipe
80/20 and SLIDE systems
Thompson rails
THK and similar rails.
Likewise for linear motion transmissio;, Acme, Allthread, Ballscrews, COGs and belts, etc. Hearing the choices you make and why will help a lot of people I think.
Cheers - Jim

[signIT]

That's right go on, it will be very interesting to see what type of construction ideas you will use everything is worth to try.

I personally don't believe thet wood can be a serious component as it moves to much with temperature and moist.

[Joe CNC]

Thanks guys, it seems like you all are in favour of us getting some proper designs done. However, the real problem we are facing is that we do not understand enough about the market side. We need to know how big this market would be. How many people would actually buy one? are we talking 10, 100, 1000, 10'000...?? also what does the market want? Do people prefer high speed and low accuracy or vice versa? are they prepared to pay $200 but not $300, $500 but not $600 or where are the market limits?
This is quite obviously not necessarily a mechanical engineering problem in the usual sense but unless we know what the market POTENTIAL is, there is not going to be a design (since we cannot work out the specs by simply using the "force").
Would anyone of you be prepared to fill out a short form with some specific questions that we need?
Thanks again for your HIGHLY valued input

Joe

[thielert]

Joe,
You’re asking the million dollar question, and the answer is that there is no one answer. If you look at what is currently on the market for hobbyist CNC mills and routers there is a vast selection of very different capacities and capabilities.
Simple rules of the CNC hobby:
-Everyone wants one, many try to build one, only 0.5% get as far as cutting a single part.
-Everyone wants a huge machine, few have room for a machine larger than 12’x24’
-Everyone wants to cut aluminum, few need to cut aluminum, the best use for these cheep hobby machines is to build RC planes and other hobby components.
-Everyone wants to hold a 0.001”, a thou doesn’t mean squat in balsa wood b/c it expands and contracts with temperature and humidity. A hobbyist machine only needs to out perform what a man can do by hand two or three fold. So holding 0.015” is awesome.
-Ball screws are all the rage, ACME was the thing last year, you only need 1/4” allthread from homedepot with a cutting board plastic nut hand tapped.
-Don’t bother screwing with your own controller design. Current limiting resistors are a waste of time and amps. Get one of the fine 3 or 4 axis chopper boards pre assembled. Works great and no problems.
-NEMA23 steppers – EBAY.. your not ready for servos or Geckos.
-You can spend a lifetime on linear rail selection, gas pipe, drill rod, BWC, 80/20, Thompson, NSK, THK. Each more expensive that the previous. Gas Pipe can be rough, drill rod and roller skate bearings is tough to beat. Checking out the K.. B.. plans, they are worthwhile and they are inexpensive.
-MSCDirect.com is good
-McMaster.com is great
-EBAY.com is awesome!

So back to the million dollar question… the answer (for you) is..
1’x1.5’ cutting area
Dremel spindle
MDF construction
Allthread
Bearings of your choice


I have known several eng students who have started what are about to. Only one finished.. and I had to sell him a finished machine just before his senior presentation.

It took me 6 months to build my first machine from KB plans. It took me nearly 2 years to build my second machine (4’x4’x1’ all Aluminum). This is not a quick, easy, or cheap hobby.

Best of luck.
Tim T

[thielert]

I forgot to adx your question of market potential. No one will buy one if you’re just a kid who makes a single machine as a college project. If you make is come in different colours and have Ron Popiel or that Austrailian guy sell them on late night TV you’ll sell thousands.

Marketing is an enigma to most engineers. The adage “If you build it they will come” or “Build a better mouse trap and a path will be beaten to your door” are bunk. You can have the best product in the world and go broke without good marketing. A talented marketer can sell crap to millions. Marketing is an entirely different industry than product development.

Look at the history of the Tupperware company. Amazing success by full separation of product and marketing. My advice to engineers.. don’t try to be marketers. My advice to marketers.. don’t try to be engineers. It is a very rare person that can do both adequately.

Best of Luck
Tim T

[jimbo]

I am confused by post #5. You say its not a kit but the user has to build it. What do you get for 400-500?

I would like to see mass produced personal use machines. Say using even dovetail ways or some simple bearing arragement. Needs built using a stable material. Needs to be modular, perhaps allowing some sort of length extensions for upgrades. Probably stepper motors with chopper drives are cheapest solution. Allow for 1/8" and 1/4" shank bits. Cutting size would probably be 2'x14" for smallest configuration, upgrading to 2'x2' and 2'x4'.

Software is also a big portion of the problem. The process needs to be more streamlined. I would like to see it almost as simple as printing something off the computer.

Marketing is a big key. If you could get the product out to a big retail store and market it as an engraving tool, modeling, etc and appeal to the kind of people that like legos, rc models, art, even woodworking. Also things are very price sensitive in todays market. I would shoot for 150-300 at most, most people can gamble that for a product as a gift or for themselves. But I really think software needs to also be a part of it. It will be hard to make a complex process simple enough for wide acceptance. Maybe have specialized packages for engraving, modeling, sculpting.

[High Seas]

It sounds like you need to do some market analysis. I'll bet there are some folks 'cross campus that do that kinda thing or are learning how. Would certainly make the effort a systems approach. Sound engineering is great - but you're right - no market - no sell, no deal.
If this is a bona-fide college/university'etc engineering project - you might contact some of the better known builders out there, and ask them what they think the market looks like. SHOPBOT is pretty well known in the woodworking circles and first attracted me to this hobby. DOn't know how many they've sold - but its the 3000 to 6000 dollar range as I recall. I DIY'd rather than spend that much. (But then again - I'm not yet to their scale 4x8). Google the available machines and do some research, categorize, develop a market survey - less than 20 questions - then start asking. Bet you'll find a solid number in less than 100 surveys!


Tim T - I always thought of Marketing as something separte from SALES - but I know it's all gotten quite blury:
Idea ---> engineering ---> prototyping---> engineering analysis---> CAN IT BE BUILT?
Idea ----->market analysis------->cost analysis -----> DOES IT MAKE SENSE TO BUILD?
.............................Product (even crap) give it to SALES ----> sell at any cost!
Just off the top of my head!
Cheers - Jim