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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Mon Feb 04, 2013 6:12 pm 

Joined: Tue Dec 14, 2004 5:45 pm
Posts: 262
CRIJ, do you have a link to share for the photo conversion?

Terry, I appreciate good old fashioned techniques and enjoyed your thread on the casting. My tech is developed and the cost for me is less than traditional methods when all factors are considered. This is not a thread about what can be done in the future, it's about what technology exists now. By starting this thread, I looking for people to share their tips and tricks that I might be able to take advantage of.

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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Mon Feb 04, 2013 6:35 pm 

Joined: Sun Aug 22, 2004 7:19 am
Posts: 5515
Location: southeastern USA
No worries, Andy, he was talking to me.

I would have preferred he start a thread on old casting techniques if he wants to talk about it instead of hijacking yours. I know what I need to know about old technology - I need to learn more about the new stuff. I could then ignore the one I don't need while reading the one that would have the information I want to learn about.

I don't need good luck - it's happening whether I pick the right Powerball numbers or not. If I need something today, I can either ask Andy to help me out or do it myself the old way. Cost is relative to value, and value is based on intensity of need.......and custom and one-offs are either just "nice" things to finish a project, or critical to get something back into productive use. Broad range of value there. I probably don't have time to do it myself the old way; so, if it isn't critical, I decide whether to pay whatever the price is or let it ride no matter what the technology.

I don't see it being as practical for large castings....I would probably use styrofoam for something like a cylinder saddle, cut with carving tools, and glued together. Nice if you can cast the cores in removable mud as part of the assembly process.

dave

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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Mon Feb 04, 2013 7:01 pm 

Joined: Tue May 08, 2007 4:59 pm
Posts: 138
Dear Dave,

As you can see I deleted my previous posts since they caused you great angst. Obviously I did not articulate my point very well so I will make another attempt.
The idea that this technology – be it laser scanning, photographic or 3d printing is a “one click” task is a gross simplification. I have been in the design industry for over thirty years. I work with 3D and yes the technology is indeed developing by leaps and bounds but…it’s not a one click task. Its has its place and is not for every application.

Now let’s look at replicating a part. Let’s say you have payed to have it laser scanned – this is probably the most accurate and cost effective method. The photographic method I am familiar with requires placing little strips of dots all over the object to be replicated – this allows the surface features and contours to be captured. Needless to say this is time consuming and your time and your volunteer’s time is better spent making money and the accuracy of the model depends on the quality and thoroughness of the job.

So now your part is scanned. Again, unless you are skilled at operating the modeling program or have a volunteer who is… oops! Forgot…that making money thing again! You will have to pay to have the raw data converted into a usable 3d model. Again this is not a one click operation meaning time and money. Of course any responsible CAD operator would want to verify the accuracy with hard measurements (time).

Next, any surface imperfections – pitting, welds, flash, dents, etc. have to be removed from the model – yes the laser will pick these up. Again this is not a “one click” operation and can be very time consuming.

Yes, scaling for shrinkage is almost a one click operation. But adding draft, core prints and part lines is not by any means – again it’s that time= money issue thing. Does your CAD operator have a thorough understanding of foundry practice? What about core? Unless the part was sectioned and scanned as well those have to be modeled from scratch – again time, time, time. Unless you are capable of manipulating the model yourself you’re at his or her mercy – Remember you can’t hold the piece in your hands until after the 3d printer has done their job at considerable cost.

Now it’s off to be printed. Most 3d printer outfits charge by mass so the bigger the part the greater the cost. Now you have your patterns and cores but…was it cost effective versus traditional methods (I count the use of foam as traditional) ?

If I were doing a small complex investment casting sure! If I were sand casting….that would take some considering.


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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Tue Feb 05, 2013 3:25 pm 

Joined: Tue Dec 14, 2004 5:45 pm
Posts: 262
Here is an interesting Fused Filament 3D Printer built on a Delta Robot platform on kickstarter http://www.kickstarter.com/projects/deltamaker/deltamaker-an-elegant-3d-printer-0?ref=live

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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Tue Feb 05, 2013 4:37 pm 

Joined: Thu Aug 26, 2004 2:50 pm
Posts: 2326
Location: Northern Illinois
Sorry for the rather acid tone of my earlier posting on this subject, but the original article cited, about plastic injection molds, was the typical combination of hype and BS. Also building an injection mold has very little relevance to our restoration work.

Now that the discussion has turned to foundry practice, there are indeed modern technologies that are helpful. Most will need a 3-D model as a starting point. While laser scanning has all that whizz-bang appeal, I dare say that if engineering drawings for the part exist, a CAD jockey can construct your 3-D model considerably faster and cheaper than scanning will. For simple parts like the pipe bracket we were discussing a couple weeks ago, good ol' measurement with a caliper and scale will get you where you want to go, again cheaper and faster than scanning.

I'll let everyone in on a little secret... very few traditional foundry patterns are built by "traditional" methods these days. Most pattern shops make extensive use of CNC mills and routers, so while the end result may be wood, it could also be be machined from aluminum for longer runs, or from a "burn-out" foam material for a one-off. Core boxes that were once made by building a pattern the shape of the core, and casting the core box around it can be easily machined from the solid. The key to all this, of course, is having a solid model of the desired casting.

The various "rapid prototyping" additive manufacturing processes also have a lot of sex appeal, but in reality are still limited in size to parts the size of light fixtures and smaller, and are slow and costly to build. They have their place, but should not be the first thought for most of the parts we need replicated.

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Dennis Storzek


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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Tue Feb 05, 2013 5:33 pm 

Joined: Tue May 08, 2007 4:59 pm
Posts: 138
Quote:
While laser scanning has all that whizz-bang appeal, I dare say that if engineering drawings for the part exist, a CAD jockey can construct your 3-D model considerably faster and cheaper than scanning will. For simple parts like the pipe bracket we were discussing a couple weeks ago, good ol' measurement with a caliper and scale will get you where you want to go, again cheaper and faster than scanning.


Spot on!


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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Tue Feb 05, 2013 6:03 pm 

Joined: Tue Dec 14, 2004 5:45 pm
Posts: 262
Scanning is one tool in the bag. It sounds like a good way to copy damage and defects though. I suppose everyone is stuck on scanning because of the earlier post about a scanned steam engine. I do not have access to a scanner. I measure objects and construct drawings in CAD or I convert 2D blueprints to 3D CAD models. The whole goal for this post was a single thread to share links and info about modern reproduction techniques. Debate is fine, but not the goal.

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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Wed Feb 06, 2013 3:39 pm 

Joined: Sun Aug 22, 2004 12:15 am
Posts: 504
Andy,

Photo to 3d conversion programs, not sure how good any of them are. The first one is the only one I know was written by a company that writes 3D drafting programs

www.123dapp.com (written by AutoDesk)

www.photo-to-3d.com
www.hyper3d.com
www.Arc-Soft.com (Mediaconverter)

-----
As far as the problems with scanning a real world item (repairs, defects, etc...) there is an easy solution. First you take the best representative of the part to copy. With a combination of files, stone bars and ginders remove excessive welds/brazing (same as if you were repairing for restoration), then take modeling clay or thick clay slurry (gushy mud consistency) as it will wash out of the part, and fill the pores and voids with the clay, also you can use the slurry to smooth sand castings. For machined surfaces, take a 1/8-1/4" slab of modeling clay and build up the surface. Once you do that your scan will be an ideal part. The other option is to scan your part defects and all, print one or two of those and use your modeling skills (without putty) and perfect the model. Now you have a choice use this perfected positive as an investment casting sacrificial core, or if you need multiples, the casting house will use this perfected positive to create the molds.

As far as costs go, within your volunteer base I am sure you will be able to find a 3D drafter or a friend of one that can sneak the occasional project in under the radar unless you need it immediately.

As fast as the 3D printing world is advancing I can see 24"x24"x24" printing envelopes (max part size) within 5 years for under $3000. Currently there is a Delta style ABS printer (www.deltamaker.com) that has a 9" diameter x 11" tall printing envelope going for $1600 - $2000, and it looks like it could be easily expanded to larger sizes with some minor changes. Most others in this price range have 4-8" cube print envelopes.

Rich C.


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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Wed Feb 06, 2013 3:41 pm 

Joined: Tue Dec 14, 2004 5:45 pm
Posts: 262
For printer access, I maintain a good relationship with the drafting department at the junior college. I cover the cost of the media.

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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Thu Feb 07, 2013 3:26 am 

Joined: Thu Nov 22, 2007 5:46 am
Posts: 2525
Location: S.F. Bay Area
Techshop (and equivalents) are remarkable resources for this sort of thing. It lets you get a lot of facetime on the software and fabrication tools for a very low cost.

Yes, you do have to learn some skills. They help.

I wanted to make "floating barn hangars" so we could pull tension on trolley wires without pulling the carbarn over. Not a difficult fabrication, except that I needed 60 of them, and it would make assembly easier if some holes were square for carriage bolts. Well about $200 worth of TechShop resources and I CNC plasma cut them all. Had to learn it all from scratch. Took about 3 evenings.


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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Thu Feb 07, 2013 1:02 pm 

Joined: Tue Dec 14, 2004 5:45 pm
Posts: 262
Techshop

That is cool. I want one here.

Also, let's talk about floating hangers. The MATA barn could use some, along with some troughs to replace the "wobbly wire", a temporary fix that has been in use since 1989. Care to share the design?

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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Sun Mar 24, 2013 6:05 pm 

Joined: Tue May 08, 2007 4:59 pm
Posts: 138
Recently I was sent this link regarding the reproduction of a part for an antique Dennis fire pump. Its a good A-Z example of what can be accomplished using 3D modeling and rapid phototyping techniques to recreate a finished part - in this case a water pump housing.

http://www.dennisfire.co.uk/p36.htm


Enjoy.

Best regards,

Terry


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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Sun Mar 24, 2013 7:36 pm 

Joined: Thu Nov 22, 2007 5:46 am
Posts: 2525
Location: S.F. Bay Area
Andy Nold wrote:
Techshop

That is cool. I want one here.

Keep in mind that TechShop is only one brand of that sort of thing. They seem to be popping up all over. So I would search more broadly.


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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Thu Oct 24, 2013 3:50 pm 

Joined: Tue Dec 14, 2004 5:45 pm
Posts: 262
Faro Arm scanning and 3D printing to replace rare parts at Jay Leno's garage: http://www.youtube.com/watch?v=q3SVTBrKyZk

Cool stuff.

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 Post subject: Re: Modern Reproduction Techniques
PostPosted: Thu Jan 04, 2018 3:22 pm 

Joined: Tue Dec 14, 2004 5:45 pm
Posts: 262
I got a 3d plotter for Christmas. It's an ANet A6. I've been reading up on plotting media, trying to figure out best filament to use for patterns, best for dielectric strength (I've got some snap switch covers I'd like to reproduce) I was interested to learn that they make a printer filament that combines polymer with wood fibers to plot "wood" and another with metal filings which results in a part that can rust and attract a magnet.

The first thing I'm going to plot is the frame for a 3d scanner. You can get the guts from Cowtech for $119 and plot your own frame. I've got a few trolley parts that I want to scan in after I get that up and running.

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