After the Millstrap/routerstrap/repstrapoko....

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WillAdams
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After the Millstrap/routerstrap/repstrapoko....

Post by WillAdams » Fri Jul 25, 2014 1:45 pm

(Does anyone else find the reprap wiki incredibly confusing / disjointed / unorganized / hard-to-read?)

Okay, the recent setback has me thinking.

What would be the best / most affordable / most reasonable option for a stand-alone 3D printer after one makes a repstrapoko?

The two most printable options seem to be:

- Simpson --- http://reprap.org/wiki/Simpson
- Tantillus --- http://reprap.org/wiki/Tantillus

Did I miss something? Simpson seems out due to the complexity of the (current) software chain and inability to make its own parts which is a shame.

Or of course, one could go w/ an Ord Bot which seems a good companion to a Shapeoko, since it uses MakerSlide as well, but given that the only 3D printed part in it is an extruder, there's no point to the repstrapping.

One aspect of this is I'd like to donate the parts for a 3D printer to a local library along w/ a pair of books (or one book in two volumes):

- Preparing to make a 3D printer: sourcing the parts, planning your first prints
- Making a 3D printer: Assembly, Calibration, Printing parts

(If no one objects, I'll be structuring the wiki page along those lines)
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

cvoinescu
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Re: After the Millstrap/routerstrap/repstrapoko....

Post by cvoinescu » Fri Jul 25, 2014 2:16 pm

I may have to wear the asbestos underwear for saying this, but there is very little point in repstrapping anyway.

I mean, it's a fun exercise, and there's nothing wrong with using 3D printed parts in a 3D printer, but, at the moment, with so many essential parts not printable, or more easily made another way, I take the more pragmatic approach of designing the machine and the parts based on the manufacturing method that works best -- where "works" includes functionality, but also availability (to me) and cost. Laser cutting flat metal parts works well for me for small runs, meshes well with MakerSlide and the V-wheels, and I can even use CNC milling for one-offs for prototypes. For cable clips, limit switch mounts and other very small pieces like that, where injection molding would be the technology of choice in large runs, both 3D printing and CNC milling work for small runs. If the part is amenable to that, laser-cut acrylic or polycarbonate would be good too. I don't have access to a brake (to bend metal), and the fabricator I use for laser-cut parts charge an arm and a leg for secondary operations, so I would not use laser-cutting and bending for a carriage, like Bart did in at least two of his machines. (If you read through this forum, this is a common theme: having to bend a part is unpopular, and sometimes results in sub-standard parts.) I would use a flat laser-cut carriage instead, and either redesign the extruder to mount directly to the vertical surface, mill a bracket out of aluminium profile, or 3D-print an adapter (but not the whole carriage).
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

WillAdams
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Re: After the Millstrap/routerstrap/repstrapoko....

Post by WillAdams » Fri Jul 25, 2014 4:24 pm

Let me rephrase the question then:

For a 3D printer, what are the lowest possible price points for?

- a mass market kit (as a datapoint the lowest shipping machine I'm aware of is the Printrbot: http://printrbot.com/shop/simple-makers-kit/ )
- an assemblage of parts plus ``free'' 3D printed pieces (assume that each person is willing to donate the filament and print time for the next) --- I'll try to find time to price out a Tantillus unless someone has a better option.

Are the two price points close enough that the assemblage might make sense for a reasonably great enough number of people that it would be worth the effort for a library to do this? (and for me to write the two books in question)

If so, is that likely to change, and if it might change, in what likely timeframe?
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

orangezero
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Re: After the Millstrap/routerstrap/repstrapoko....

Post by orangezero » Fri Jul 25, 2014 5:12 pm

The google group for delta printers has had a "pay it forward" program for quite some time. I think a lot of people have had good luck, and everyone seems to be doing their job. Essentially, someone sends you free printed parts for a kossel mini (I think, it varies) and you agree to print off parts for two people on the list in the future. I don't think you can get cheaper than that, if you are okay with a delta.

A delta was my first printer, and I made one up using only one printed part. Local lab's printer would have taken forever on their slow machine. I improvised with carriages from scrap 1/4in plywood, and it worked well for over a year.

I think a place called deltaprintr has kits that are pretty cheap, but also sells set of their wheels and carriages which might be cheaper if you can do some work yourself.

I think for price, it is hard to beat a printrboard, although I'd probably go with the azteeg x5 if I was starting over. The ease of uploading new "firmware" settings are worth the extra $20 or so of the newer board. Having to use arduino IDE and then upload, reset, etc gets old rather quickly.

I think someone with a shapeoko could cut up some carriages and brackets to hold the extrusion together rather quickly.

http://www.ebay.com/itm/80-20-Inc-1-Qui ... 0749387664

This is cheap, and would allow linear motion with three v-wheels on the two pseudo rails. Most seem to want to just grab someone else's design like the kossel or 3DR.

People complain about the deltas, but if you are okay with some math and already understand g-code in a cnc machine, it shouldn't be too difficult. Deltas are just too darn cool to look at to not consider.

WillAdams
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Re: After the Millstrap/routerstrap/repstrapoko....

Post by WillAdams » Fri Jul 25, 2014 5:43 pm

Thanks!

I agree the deltas are very, very cool, and will add them to the consideration.

On the bright side, I seem to be printing again.
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cvoinescu
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Re: After the Millstrap/routerstrap/repstrapoko....

Post by cvoinescu » Fri Jul 25, 2014 8:18 pm

Will, a lot goes into the price of a kit. I'm sure the Printrbot makes some compromises to get to that price, and they may make a smaller profit on that kit but make it up from the sales of upgrades, so you don't really know what the kit costs based only on the price they sell it at.

The size of the investment also affects the cost enormously. If you go large enough (say 1000 kits at a time), the parts will be cheap, you'll be able to use cheaper manufacturing methods with upfront tooling charges (e.g. custom aluminium extrusion instead of machining, stamping parts instead of laser-cutting them, bending and spot-welding parts instead of assembling them from several flat plates, powder-coating cheap steel instead of using stainless or aluminium, and so on), and transport will be a whole lot less. If you make 50 or 100 at a time, you can't afford to hire a purchasing manager to find the suppliers for you, you have to use local (expensive) fabricators for some parts, and you can't aggregate the shipping of the imported parts -- so you'll pay more for the parts, and you'll pay each supplier standard shipping rates -- and they do add up! The perceived quality of the machine is affected too, because if you do a lot of them at a time you can play with finishes and colors, you can screen-print logos, have custom-made shipping boxes, and a number of other little things like that.

An important difference between the two options is that a complete kit is much more appealing to a significant number of people, and will sell more units. (That's probably one of the more unexpected lessons I've learned selling eShapeoko kits: I'm perfectly comfortable sourcing parts from different suppliers, or buying them as separates from the same vendor, but plenty of people aren't.)

To sum it up, if you take the word 'mass' seriously, a mass-market kit can be very cheap, to the point that the other option would not make any sense (but you need capital in the five or even six digits, probably). If you want to start small, both options are valid, but keep in mind that people like you and me overestimate the appeal of the DIY aspect of your second option.
Proud owner of ShapeOko #709, eShapeOko #0, and of store.amberspyglass.co.uk

WillAdams
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Re: After the Millstrap/routerstrap/repstrapoko....

Post by WillAdams » Sat Jul 26, 2014 1:05 am

Not interested in selling kits. I simply included them to establish a baseline for price / perceived value. Curious to see how low that price will go.

So, if we can get the pricing for the purchased parts below that of the printrbot, maybe this would be workable. I'll start in on researching, and will continue to fill in the wiki w/ an eye towards the possible book.

I'm still faintly mystified that Inventables isn't selling the Ord Bot, but I'd guess that's an exemplar for the difficulties you noted.
Shapeoko 3XL #0006 w/ Carbide Compact Router w/0.125″ and ¼″ Carbide 3D precision collets

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