Hi: Time really flies. Have wanted to write a new addition for some time now, but those round to its always seem to pop up. Usually it is because there is a deadline to meet and as usual, ten other things need attention. On the other hand, I always am looking for something new to write about. However, at present, the game in town still appears to be advanced manufacturing. This technology is not new, being a NASA tool for making objects for space, way back in the 90s. Obviously expense was no problem because they just couldn't find a different way.
Currently, in its wisdom, government has invented a new word called commercialization. What this means is that the government has put out a large outlay of funds for research and now they believe that it is fair to get a return on their investment. Therefore, this expensive technology developed by NASA so many years ago becomes today's commercial reality.There are several factors that make this more practical for consideration. One is the cost of materials. Everyone knows that things cost more today and when they are not readily available, the greater the cost.
Unfortunately most things start out as a solid bar which is forged, extruded or machined, or in some way made into a desired shape, say a gear. To do this, material is removed. If this material is, say a superalloy, the material is expensive, and as much as 80% can be removed as scrap chip. In addition, to make the desired shape, skilled labor is required to satisfy exacting dimensional control to permit the part to function in service and to mate with other parts. I think you can start to understand where I am going in relation to cost.
In addition, there is the matter of time involved. Quite often to just get the material to shape to size can require months. On top of this, in many cases, either one or a few items are required, which in turn adds to cost. Therefore an opening to drive this technology to commercial reality.
This now introduces a complete new industry entitled Advanced Manufacturing. The title covers a myriad of things, but in its most practical sense it requires an exact three dimensional drawing of the object to be made. This can be rapidly produced using a computer and programs developed to create the desired shape. Once the desired object is created, it is then a small matter to make the shape exactly to the size, and very close with little finishing, to the desired dimensions without one chip of scrap being generated. This is accomplished by creating a platform to contain a small layer of powder distributed and raked to a certain height. Once the powder is distributed, normally either a laser or an electron beam traverses the layer of powder, melting the incremental area designated by the three dimensional model. The only powder that is melted is the area that the laser or electron beam traverses. Therefore blind holes can be made, large pockets of undesirable material eliminated, and a desired shape, no matter how complicated be made without creating one machined chip. Once the desired increment of thickness has been formed and melted, another layer of powder is raked over the layer just shaped, again computer driven to form the next small increment of the part, built on top of the layer just created. This process is repeated until the part is built to the exact design of the desired part. Then, with minor finishing the part is ready for service.
The process has now been found to be useful for making parts like prototypes for creating dies for casting, forging and powder metallurgy molding, as well as first-kind products. If the part is not exactly to what is desired, the part is discarded, adjustments made to the three dimensional model, and again a first-kind part is produced in a matter of days, rather than months. Furthermore, a large facility may not be required to make the parts, but a part may become defective and using the technology described either repaired or made in the field, putting the equipment back into service quickly.
Although dormant all these years, this technology is now rapidly being accepted as being an economical process to produce a few parts quickly, in a few days, rather than months. It also is beginning to be understood as a way to quickly repair or create new parts for equipment that is as much as 50 years old and considered as obsolete and parts for replacement unavailable. Technology does move on.