[AT] repairing machined arts

[Henry Miller]

Traditional casting is much cheaper, once you pay off the cost of the making the pattern. We (John Deere) had someone looking for a shift fork for the transmission in their 1991 tractor a few years ago. No spare parts left in inventory, and the pattern was destroyed years ago, so we 3d printed one from the engineering drawings. Cost was just under $500, without markup. If the pattern still existed the cost would be about $20 including markup to pour another one. 

Of course if you need a new block a pattern exists, so the 3d metal print is what you get. If you can find a few others who need one though investing in a pattern is the way to go. 

3d printing plastic is cheap and works okay for a lot of things, but it isn't enough quality to replace most parts on our tractors, even ones where plastic would be better. 

-- 
  Henry Miller
  hank at millerfarm.com

On Fri, Dec 6, 2019, at 4:19 PM, szabelski at wildblue.net wrote:
> If you remember the TV series “Myth Busters”, there is a new show 
> emceed by one on the guys (believe it’s Jamie), who does a lot of 
> similar things to what they did on MB. I caught one show where they 
> were making an Ironman suit made from titanium so they could 
> prove/disprove some of its capabilities. Some of the parts for the suit 
> of armor were made using 3D printing and powdered titanium. Didn’t take 
> that long to make the parts. I think I also saw a program somewhere 
> were something was being made using powdered iron (????).
> 
> Don’t know how well other metals could be adapted to a process like 
> that, but if the technology can be properly developed, and the cost can 
> be kept down, could this be the beginning of the end for all types of 
> machined/cast parts? If so, would a repair shop still have to carry a 
> large inventory of parts, or just make a needed part using a 3D printer 
> and the proper material on the spot as needed?
> 
> “Yes sir, you say you need a new engine block for your 1920 vintage 
> tractor? Just come back tomorrow and it’ll be ready.”
> 
> Carl
> 
> 
> ----- Original Message -----
> From: Ken Knierim <ken.knierim at gmail.com>
> To: Antique Tractor Email Discussion Group <at at lists.antique-tractor.com>
> Sent: Fri, 06 Dec 2019 15:16:47 -0500 (EST)
> Subject: Re: [AT] repairing machined arts
> 
> Some progress has been made toward taking digital photographs of the
> original part and creating a 3D model from them (photogrammetry). I have
> the software (as part of a 3D printer package) but have not tried it yet so
> I cannot vouch for the accuracy. I'm still new to 3D printing but we've
> already put several parts into production systems... it's got its place.
> The photogrammetry process might be a decent place to start if you want to
> make a casting but I'd question accuracy for finished parts. The laser scan
> technique would be better in my opinion.
> 
> Something along similar lines for making parts is 3D metal printing. The
> Rutherford rocket engines are made using this technology. It uses an
> electron beam rather than a laser for melting the metal and requires a
> vacuum chamber for manufacturing but obviously works with high pressures
> and temperatures.
> 
> Photogrammetry software:
> https://all3dp.com/1/best-photogrammetry-software/
> 
> Rutherford rocket engine:
> https://en.wikipedia.org/wiki/Rutherford_(rocket_engine)
> 
> I see these as interesting ways of creating parts. As with anything, it's
> going to take some work to perfect. I doubt it would be affordable for
> tractor parts for awhile.
> 
> Ken in AZ
> 
> 
> 
> On Fri, Dec 6, 2019 at 10:48 AM Jack <jacktractor at live.com> wrote:
> 
> > The shortcoming of this for the repair of unavailable tractor parts is
> > that you need a Cad file of a good part first.
> >
> >
> > https://www.imeche.org/news/news-article/feature-retrofit-transforms-legacy-machine-tools-to-keep-worn-parts-in-use?utm_campaign=PE%20newsletter%2C%206%20December&utm_source=email&utm_medium=PE%20Newsletter
> > _______________________________________________
> > AT mailing list
> > AT at lists.antique-tractor.com
> > http://lists.antique-tractor.com/listinfo.cgi/at-antique-tractor.com
> >
> 
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