Looking for community input! College senior project.

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Luxx
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Looking for community input! College senior project.

Post by Luxx » Thu Oct 09, 2014 12:03 am

I'm beginning my Senior Project at Western Washington University for my Manufacturing Engineering Technology CAD/CAM degree and I need some help from you guys.
My project is designing a DIY router table with a minimum work envelope of 24 in x 48 in x 5 in. A goal of this project is to bring the cost down and give the community a common set of well documented build instructions (similar to what the Shapeoko project has done).
I'm still in the research portion of the project, so I am asking the existing community here:
What is stopping you from building a larger machine (than a basic shapeoko2)?
What is stopping you from buying a larger CNC machine?
What are your top priorities when looking for CNC machines (to buy or build)?

Thanks for the responses in advance.
Shapeoko2 #3529 - DW660, Nema23 X+Y, Reinforced wasteboard.

WillAdams
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Re: Looking for community input! College senior project.

Post by WillAdams » Thu Oct 09, 2014 12:49 am

Luxx wrote:What is stopping you from building a larger machine (than a basic shapeoko2)?
Mu. I upgraded my Shapeoko 1 to have a 1M Y-axis.
What is stopping you from buying a larger CNC machine?
The expense of it, and the difficulty of finding somewhere to put it / operate it and the difficulty of moving a larger machine --- my SO1 (see signature) is just barely man-portable.
What are your top priorities when looking for CNC machines (to buy or build)?
- Affordability
- Open source / well-documented
- flexibility --- I've already worked up a 3D printer extruder add-on for my SO2, next up are a laser cutter/engraver and a drag knife

Design aspects I'd like to see considered:

- a machine designed to be mounted / used at an angle like a vertical panel saw (this would probably not allow 3D printing though)
- a design where rather than custom plates one uses several short lengths of standard extrusions bolted together --- this might help on the cost aspect
- additional axes --- one of the goals for having the 3D extruder is to use it to make the parts needed for adding a rotary axis and a drive shaft on my SO2.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

Schruminator
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Re: Looking for community input! College senior project.

Post by Schruminator » Thu Oct 09, 2014 1:44 am

Luxx wrote: What is stopping you from building a larger machine (than a basic shapeoko2)?
What is stopping you from buying a larger CNC machine?
What are your top priorities when looking for CNC machines (to buy or build)?
To be honest, it sounds like you're trying to design a ShapeOko. Given as how the SO opened up the CNC world even more to amateurs not only with the design, but also the cost point, it pretty much meets the requirements you're aiming for. Well, at least compared to the options prior to the SO-- either you had uber expensive ($10K +) machines for the manufacturing world or $2-4K kits for the garage hobbyist.

Nothing is stopping me from upgrading my SO2. My current machine is 1m by 1.8m (with a bit smaller usable work area) and a working height of 4" more or less.

What is stopping me from buying a larger, "more pro" machine is the cost and support. If something goes wrong on my SO2 I know that I have a community to lean on (and not some expensive technician or area rep) and the fix is unlikely to break my budget. I can't imagine there are too many "cheap" fixes on a $10K machine.

My priorities for a CNC were to not break the bank while still creating a machine that would not limit my imagination. If I can think it up, I want to be able to create it. For the woodworking I do, the SO2 fits that bill quite well.
1.8m x 1.0m SO2 #3638 / Vectric Aspire / ACME Z-axis / View my photography at http://www.mschrum.com

Improbable Construct
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Re: Looking for community input! College senior project.

Post by Improbable Construct » Thu Oct 09, 2014 1:56 am

I spent about 20 minutes working on a reply but as I went to post it I read Schruminators reply. I agree with everything he said and he said it better than I did. :)
That being said don't feel like you have been shut down. This is an open and helpful community. If you need help or have more questions, please keep this thread going.
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Luxx
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Re: Looking for community input! College senior project.

Post by Luxx » Thu Oct 09, 2014 2:04 am

Well the project has already been approved by the department and I will be building one for myself, a second one to be modified for a professor's research paper, and a third for a local makerspace.
I am trying to do something very similar to the Shapeoko project, but with the idea that it will be a larger scale machine from the beginning.
I like my shapeoko2 and have enjoyed the last ten months I have owned it, but when it is scaled up it has some short comings.
One of the big goals will be to maintain high accuracy with the larger work bed. (My Shapeoko2 is under .005" accuracy, even did an experiment for a class to verify and optimize that)
Another goal will be reducing custom parts ( i.e. lowering the custom plate count)
Shapeoko2 #3529 - DW660, Nema23 X+Y, Reinforced wasteboard.

WillAdams
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Re: Looking for community input! College senior project.

Post by WillAdams » Thu Oct 09, 2014 2:25 am

Luxx wrote:...when it is scaled up it has some short comings.
One of the big goals will be to maintain high accuracy with the larger work bed. (My Shapeoko2 is under .005" accuracy, even did an experiment for a class to verify and optimize that)
The trick will be to improve on the accuracy w/o significantly affecting the price point --- that's a tough balancing act and there's a pretty direct tradeoff.
Another goal will be reducing custom parts ( i.e. lowering the custom plate count)
That's a good place to begin --- as I noted above, I suspect that one could make carriages up out of short lengths of extrusion fashioned together --- not sure how that will affect the pricepoint though.

Looking forward to seeing what you come up w/ on all fronts though.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

Luxx
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Re: Looking for community input! College senior project.

Post by Luxx » Thu Oct 09, 2014 2:31 am

Thanks
Yeah the accuracy / price ratio is the tough balancing point. There are a few things that can be done without too much cost to help improve accuracy and repeatability.
I figured I would come here and ask others what they would like to see and get some opinions from the community that is already running an open source CNC. Hopefully it will be a machine that is built by more people than just myself, as part of the project will be providing full build instructions for that purpose.
Shapeoko2 #3529 - DW660, Nema23 X+Y, Reinforced wasteboard.

edwardrford
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Re: Looking for community input! College senior project.

Post by edwardrford » Fri Oct 10, 2014 8:39 pm

For the sake of education, a couple of points:

1.) 80/20 principle applies to the current Shapeoko design: 80% performance for 20% of cost compared to 'higher end' machines)
2.) Each .001" in accuracy you want to increase, will cost more than the previous .001".
3.) Depending on how the parts are being manufactured, reducing the custom plate count won't necessarily change your cost. Changing from S1 to S3, I increased the custom plate count from 5 to 6 and actually reduced the cost because the parts are laser cut. So by simply reducing the amount of steel being used reduced the cost. If you were to some how design an all-in-one plate that worked for every part of the machine, and then had that plate stamped, you could potentially reduce the cost per piece after you absorbed the initial investment of the die. Assuming your quantity were high enough.

To answer the "what's stopping you from a larger machine" question:
1.) Space is a huge concern. Yeah, i'd love a 5'x10' machine, but between the actual footprint, the pedestal, and the vacuum, the cost of space is too high to justify. And obviously the cost of the machine itself :-)

-Edward
Shapeoko 1 #0 - a couple of upgrades.
Shapeoko 2 #0 - a couple of upgrades.
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danimal
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Re: Looking for community input! College senior project.

Post by danimal » Sat Oct 11, 2014 3:59 pm

The other posts hit the nail on the head, so I wont repeat it. But what I did want to add was that there are many limitations to the CNC router platforms across the board. The design is limited by z axis travel, spindle power and overall rigidity. The other answer to the size question is that I don't need a very large machine 99% of the time. I have made mine 24" x 48" roughly and I almost never use more than a square foot for my projects.

If it were me I would design a ridged machine using the control structure of the Shapeoko. I would design a x y table assembly that utilizes the aluminum extrusions, and design the machine around metal work. What works for metal will work for everything else, but the reverse is not true and metal on any high speed router is a nightmare. There is competition in this area as well, but there seems to be a gap between tiny closed box machines, and several thousand dollar machines. A platform designed around a bench-top milling machine at the price point of the shapeoko would be a gold mine. The mill that I have uses a brushless DC motor as the drive for the spindle and it is super quiet, powerful and cuts through steel and aluminum like butter.
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RT0701C Spindle || dual y motor || x axis nema23 with custom carriage 1000mm length || z axis nema23 linear rail upgrade with 1/2-10 ACME

WillAdams
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Re: Looking for community input! College senior project.

Post by WillAdams » Sat Oct 11, 2014 4:31 pm

danimal wrote:A platform designed around a bench-top milling machine at the price point of the shapeoko would be a gold mine.
Don't the bench-top milling machines start at about what a Shapeoko kit costs?

$599.99, on sale for $549.99 --- http://www.harborfreight.com/two-speed- ... 44991.html

ISTR Harbor Freight having a CNC mill for a while, but not seeing it now.

We do list some mill conversions on the wiki: http://www.shapeoko.com/wiki/index.php/ ... Conversion
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

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