[rp-ml] Old memories discovered

From: Elaine Hunt <ewhunt_at_bellsouth.net>
Date: Thu, 7 Feb 2013 16:34:22 -0800 (PST)

History of Stereolithography Not sure what year these were written     P M Dickens   I first got introduced to Stereolithography on Thursday 29th November 1990. I was doing a project for Ford at the time on low cost tooling for die-casting. We had a meeting that was attended by Rolf Husemann from Ford in Cologne. At this meeting he pulled out of his bag some plastic parts and proceeded to explain how a process called Stereolithography had made them. Eureka!!! We started to do work with Stereolithography parts to investigate automated finishing techniques and the possibility of electroplating them with copper so that they could be used as electrodes for Electrical Discharge Machining. Owen Baumgardner at Texas Instruments (now Raytheon) kindly supplied these first parts. In 1992 I organized the 1st European conference on Rapid Prototyping at the University of Nottingham. We continued doing research on applications for Stereolithography and in 1994 I purchased an SLA250. We then did work on the Stereolithography process as well. One of the areas of work was investigating the way investment casting shells failed when using QuickCast parts. This led to a Ph.D. for Richard Hague and a patent held by Richard and myself on what is now QuickCast 2.0. This has been licensed to 3D Systems. In January 1998 I moved to De Montfort University and continued the research there. The main area of work connected with Stereolithography has been on Direct AIM tooling and we have had a lot of success with this. As I write this 3D Systems engineers are commissioning the SLA7000 that has been installed to support the work of our research, teaching and training.     Al Dewitt The way I started in RP was pretty interesting along with some luck.  One of the guys (Klaus) in the development-engineering department at GM where I worked (1986) was nearing retirement and used to spend a good share of his day reading magazines.  In Forbes, there was a two paragraph blurb about this new process that could make prototypes overnight.  Klaus was interested, called Forbes to get a phone number, and had noted the number along side the highlighted paragraphs in the magazine.  The magazine clips were circulated in the department for all to see.  My boss had noticed it, asked if I was interested in looking into it or would I prefer to have Darryl, a young intern working with me look into it.  I told my boss that I would look into it.  The rest is history so to speak. I called Ray Freed and tried to arrange a trip for me to see what they were doing.  Ray resisted saying that they were not ready and instead wanted to come see us.  Shortly after, Ray and Chuck came to see me at GM.  Not too long after I talked them into letting me see what Stereolithography looked like.  Chuck had used two HP plotters, one horizontal and one vertical, for his machine.  The vertical plotter was the Z stage and the horizontal one was dragging around a fiber optic light pipe to bring the UV to the surface of the resin, which I think was a Loctite glue.  I still have the part that was made in about a four-inch diameter cup of resin.  Chuck had done the programming in BASIC as I remember it. GM went on from there to order machine serial number one from 3D, about a year and half from first sight to placing the order.  There was a huge hurdle getting past our legal department.  Baxter claims to be the first service bureau because they had their machine running before ours but we had machine number one.  Our old machine is now in the Henry Ford Museum.  We had to have special wiring on our machine to meet GM standards.  There was an added interlock on the machine that flashed red lights outside the doors, locked of course, so that anyone on the outside would know that there was dangerous laser radiation inside the room when the machine cover was off, about seven milli-watts of danger.             GM also sent me to an ophthalmologist to make sure that I did not have any scars on the retinas of either eye before I could work around the laser.  They even took pictures.     Chris O'Neal Yes!             I remember it being called "generic" we really couldn't think of a name for it. Designing the part was a group effort. Everyone in the group took turns adding geometry to it. It didn't matter if we knew solid modeling or not. The Aries system was like that. Ron Soucy, being more experienced, got to cut the slots in the side. The cantilevered rectangle geometry of different lengths was Dick's idea. The cones were my contribution. We modeled it in the morning in the lab. Guy Bourdeau came in at about 11:00 I remember he added his opinions.. not sure about geometry.   Is the .stl file still around?             The file was good enough to come up in Solidview. The Solidview software made a few rumblings about file size but it looks like it will be a good file. The part is up in the Y-axis. Aries put all of the parts into the Y-axis. Then the SLA machine needed to be told that it was going to swap the Y and Z-axis so that it would build.       Back in '91, GE & Textron were building an advanced gas turbine for an Army tank.  The engine had a high tech lubrication module, the heart of which was A very complex casting.  I worked at Textron then, and we used SLA to get aluminum investment castings.  It was an arduous adventure but it worked!  3D still shows miniature copies of the model at trade shows.  I'd be happy to contribute, but there are others who could tell this story better.     Bob Harmon In the old days we were using the Desoto Resin on our SLA 1.  This resin  was extremely brittle compared to the resins we use today, so finding a good use for the SLA technology in house was a challenge for me.  I was told by my management when we first received the SLA machine: "here is a brand new technology, make it work".  One of the first useful applications for SLA at Apple was making different fan designs for are computers to try and make them quieter.  This was a good application because the complexity of the blades would have been impossible to machine in house.  I made several different designs that were tested in a sound chamber inside our computers for evaluation.  The designer told me one day that he showed the V.P. of product design one of the SLA fans.  He said that as the V.P. was looking at the part he accidentally dropped it on the carpet and it shattered in many pieces. As he told me this my jaw dropped, thinking I was in trouble, but on the contrary he told me the VP was upset with himself for dropping the part and apologized over and over for braking it.  An interesting side note to this story is that after all the different extremely complex fan designs we tested, it turned out that the original simple design still was the quietest.     Dr Matt Murphy of University of Liverpool says,I can do a bit on use of SLA as final manufacturing process - i.e. making flight ready parts. This is developmental at moment but could point toward future direction. Let me know - I will need to get defense security clearance which takes some weeks.   Tom Kenney I was part of a two man team developing a computer controlled lubrication module at Textron. The centerpiece of the module was a pump whose housing supported all the other components. We ordered the pump & housing from Nichols Aircraft, who worked directly with 3D to get the casting models. It was a great, technically successful project that never left the ground (end of cold war & all). Before it was over.... ·         The engineer at Nichols went crazy & became a marketing manager at another company. ·         The piece of Textron I worked for disappeared. ·         I replaced the engineer that left Nichols. The project introduced me to RP. When I came to Nichols, I learned that they used RP to get castings for new products fairly often. I attended the ‘96 RP&M conference in Detroit to learn more. Since then I have become the RP guru for Nichols...that’s why I’m on the list. We’ve used RP for sales & marketing, concept validation, fit check models and investment castings, using SLA, SLS & Z Process. It seems we’re always pushing the envelope of investment casting with RP models.Some have come out great, some not so much.    Derek Smith, Motorola Yes, it is true that my wife and I were married with SLA rings. Funny enough, it has become one of those stories that we often tell when people ask about our engagement. The story goes like this: Shayne (my wife) and I were taking a trip to South Africa, where she grew up. Her grandparents have a large farm, and on the farm is a particular mountain. Shayne often mentioned that the mountain was one of those special places on the earth. The plan was for us to hike the mountain and have lunch, at which time I would pop “the question”. So, I created a ProE design of a ring design that I thought she would like, based on various comments, and brought the SLA on the hike. Well, she said yes, and we broke off a small piece of the rock at the summit where we ate lunch. I brought the stone back home, cut it down, and secured it in the ring. When we got married, I also made a ring for myself using SLA. We wore the rings for several weeks and then moved to the durability of gold. Each year on our anniversary, we bring out the SLA rings and wear them for the day. We figure they should hold up for quite a while that way. This October will be the 4th year that we bring out the rings!  It is kind of funny the reaction we get from people when telling the story.  Some “get it”, and others just look at what it cost to produce that particular ring, and miss the whole point. If Shayne wasn’t someone that I thought would “Appreciate” the meaning of this, I don’t think we’d have gotten married. I think it all depends upon whether it is viewed as a symbol or an object. There is an interesting correllary to this story in Ayn Rand’s “Atlas Shrugged”, which I read last year. One of the main characters (Hank Rearden) invented a new metal that took years to develop. During the first “pour” of this new alloy, Hank took a small sample and fashioned it into a relatively crude bracelet. It was symbolic of all his efforts and he couldn’t wait to present it to his wife. I won’t spoil it any more for those who haven’t read the story.          Elaine Persall-Hunt Remembers:      I worked for nine years as the only computer software and hardware support person for the College of Engineering when I decided I needed a change.  When word got out that I was interviewing, I was summoned to Dr. Larry Dooley’s office and the door closed. Since Dr. Dooley was chair of the college computer committee I fully expected to get a pep talk about remaining in my job.  Instead, he handed me a plastic object and asked me to tell him how it was made. I explained the possibilities and with each explanation his smile grew larger until he told me it was first a liquid and that a laser has solifided it.  Then he asked me if I would like to be trained to run the machine and come to work for him.  This new job would be only a contract for two years.  Ten years ago I left a secure job to take a two-year contract to run a machine with less than 100 existing in the world. When I went to 3D Systems new facilities in Valencia for training my classmates included Owen Baumgardner (TI-Rayethon), Paul Blake (Stratasys), Rose Hummel (Cascade Engineering), and Madu Raman (Clemson University).  Our training class was taught by Joe Mooring.             One of the fun things we did early on was solve the of ‘used resin’ disposal. Since we used alcohol to clean the acrylate resins off the models, the easiest method of disposal was evaporation. When all the alcohol was gone, one to two inches of goo was left in the bottom of the container.  Some people sat this goo in the post cure oven, some sat it in the sun, but I decided to use it to make something.  I bought some old glass molds used back in the 60s to make cast resin grapes and poured the contaminated resin into them, put them in the oven and let them cure for several weeks as other models were finished.  Then I would break off the outer glass, sand down the stem area, and used them as balls.  I called them “Toxic Toys” and they provided many hours of entertainment for our students.  This was the era of SLA models that broke with a touch and these balls not not break but bounced when dropped. Therefore, the challenge became what would break them and soon they were taken to rooftops and dropped as well as thrown at concrete walls.  Discussions were held on the possible usage of these ‘Toxic Toys” and many inventive ideas were generated.  I have not tried any of these toys with the epoxy resins but may make a few just for comparison and laughs.    Glyn Churchman My earliest involvement with SLA was, according to my records, a silicone rubber tool/urethane cast parts molding job Prototech did for a company named Data Image, in Irving, Texas on 6-8-1990. They changed their name to Concurrent Technologies in 1991 and in January of 1993, went out of business owing me $8,000.  As far as I know, I was the first model making firm in the Southwest to utilize SLA for patterns for the prototype molding of parts. We had many satisfied customers, who were excited about the process. Of course, the acrylic parts broke if you breathed on them and also warped easily. You only had one chance to make a good mold from a SLA!  I think it might have been mid-‘94 before another SLA bureau came on the scene. It seems to me, that in this part of the country, those that tried to do SLA failed fairly frequently. One local company tried to do in-house SLAs and had a MCP casting machine.  They took in outside SLA work but could not justify the cost and fairly soon closed the prototyping department. Only companies like Texas Instruments had the money to keep this new technology in-house. Now lookwhere we have come!
Received on Fri Feb 08 2013 - 02:28:22 EET

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