The Cool World of 3D Printing – Introduction
By Mark L. Casey | March 21, 2012
Many people are being introduced to the amazing world of 3D printing. For those of us who have been involved at various stages of product development and manufacturing, 3D printing is not all that new. However, up until recently it has gone by a different name. The technology now known as 3D printing has been known for decades to be a subset of rapid prototyping.
Let’s first peek into the world of rapid prototyping to properly locate 3D printing. Rapid prototyping, as the term implies, is any method used to rapidly create a model of a desired part or product. For example, let’s say you are designing a part that will go into a final product. You are creating the front door that will go in an automatic coffee machine. In the final product your door part is going to be made of plastic in a high volume injection molding factory.
In order for the production factory to create thousands of units of your door per week, they are going to create a steel mold (also called a tool) that will form the part when molten plastic is injected into it (thus the term “injection molding”). That tool is going to cost tens of thousands of dollars to create. The same principle applies to die casting, sheet metal fabrication, and many other production technologies.
Before that mold is created, you and your company want to make sure that the part you have designed is correct. If something is wrong with the way you have designed the part, the steel mold is going to be wrong as well because it will be created from the same three-dimensional Computer-Aided-Design (CAD) file that you used to design the part. If the mold is wrong and has to be changed, it could be a very costly repair. It would be a form of gambling to pay for the tool shop to create a mold from your CAD file without your having a chance to be absolutely sure that your design is correct.
So, before you commit to “cutting steel” and creating the mold, you are going to want to do a rapid prototype. We know that your end product is going to be made of injection molded thermoplastics, but what about your rapid prototype? You have many choices of material. Since what you are really wanting to check is the “form, fit, and (maybe) function,” you are going to select a material that will allow you to verify these characteristics. You could opt to have the part prototyped in plastic, metal, wood, or potentially other materials. You want to be able to hold the part in your hands, measure it, and see how it fits in with the other parts in the final product. Those other parts will also likely be prototyped.
Continuing with our example, let’s say you have decided that since the end product will be plastic, you want your prototype to be made of plastic as well. How will the plastic part be prototyped? There are a couple of options here as well.
- Machining. The oldest method would be to have a machine shop begin with a block of plastic and to machine away material using a variety of tools and techniques to create your part. The process may be well automated or more manual in nature, which requires the touch of an artisan. Machining usually results in a very nice prototype. This method is appropriate in very small volumes.
- 3D Printing. A newer method would be to utilize one of several processes that are now known as 3D printing. These are “additive” processes that we will look at in more detail in upcoming articles. In essence, your CAD file is loaded into an expensive machine which then lays down thin layer upon thin layer of material and builds your part as you designed it. When the machine is finished, a technician may then do some final touches to your part. This method is appropriate in small to moderate volumes (depending on the machine).
Both methods have specific costs and timetables to them. Both methods are used frequently by engineers and designers. These professionals have known for years about what is now called 3D printing. They have known it by the acronyms for the various technologies like SLA, SLS, and FDM.
Now the new term “3D printing” is allowing a larger audience to imagine the possibilities of this technology for applications beyond rapid prototyping. What if we remove 3D printing from the domain of product development and look at it in a different light? What if we think of it as a way to manufacture products on the spot from an existing database of CAD files? A very good example of this approach is revealed in the Ted Talk video by Lisa Harouni of Digital Forming. See if this video opens up some possibilities in your mind:
Look for future articles about the specific 3D printing technologies that are available.
Topics: 3D Printing, Design, Die Casting, Manufacturing, Metals, Product Design, Products, Rapid Prototyping | 1 Comment »
What is Draft?
By Mark L. Casey | February 16, 2012
Given that this is a blog about engineering, design, sourcing, and supply chains, the draft I have in mind is not:
- A document step (as in first or final draft)
- The NFL Draft
- The process of selecting individuals for military service
- Beer from a tap
The draft I have in mind is design or engineering draft. In the process of designing a plastic or die cast part, draft is very important. As I work with clients and my suppliers on the design and manufacture of parts, inevitably the discussion will turn to draft at some point.
Put simply, draft or draft angle is the required taper in the tooling that allows the molded or cast part to be more easily extracted from the tool. You may want your part to be exactly the same inner dimension at the bottom that it is at the top (with vertical walls). However, if the open end of the cavity isn’t a little larger than the base, the part may not be able to be extracted from the tool reliably. Therefore, engineers will design in a draft angle (think of a plastic drinking cup). This is often expressed in degrees of draft or in actual dimensions (inches over inches or millimeters over millimeters).
You may be wondering what if your part MUST be the same dimension at the bottom as the top (ie: perfectly straight sides). That is sometimes do-able with a highly polished tool, but it may result in drag marks or release issues.
Draft is an issue primarily for injection molding and similar processes with material that is not very flexible. With materials like the silicone used in silicone keypads, we can get away with tools without draft because of the flexibility of the material.
So, in your conversations about design, expect the conversation at some point to turn to draft.
Topics: Design, Die Casting, Product Design | No Comments »
Vital Patent Info for Inventors
By Mark L. Casey | October 7, 2011
Inventors are faced with a lot of legal questions about how to protect their inventions. Late night television is a frequent place for companies to sell you on using their services to protect your invention. We thought we would ask a true expert in the field.
James Babineau is an intellectual property (IP) attorney with Fish & Richardson P.C. in Austin, TX. Artful Sourcing asked Jim a few questions that may be helpful to you.
AS: Jim, what rights do I enjoy if I am granted a patent from the USPTO for my new widget, and for how long?
JB: The grant of a US patent is only the grant of the right to ask a Federal court to order an infringer to stop using your invention without permission, and to recover damages for past infringement. The first common misconception about patents is that they are self-enforcing. If you find someone infringing your patent, there is no US bureau of patent enforcement that will go tell them to stop. You have to file a civil suit, at potentially great expense to both you and the infringer, to enforce your patent right. The second common misconception is that your patent gives you the right to practice your invention yourself. But to the extent that your invention is an improvement on an earlier invention, practicing your improvement may necessarily require practicing the earlier invention, and thus require a license from that inventor. It is not the job of the patent office to determine infringement, and granting you a patent does not mean that they’ve concluded that practicing your invention isn’t blocked by an earlier patent.
This is easier to understand when you keep in mind that the USPTO doesn’t grant patents for widgets per se. They grant patents for inventions. Any given widget may embody dozens of separate inventions. A data processing chip is a good example of a small ‘widget’ likely subject to multiple patents.
AS: How new, special, or different does my widget have to be in order to be granted a patent?
JB: In all countries, the grant of a utility patent requires that the invention be not only new but exhibit something more than just novelty. In the US, the real hurdle for most inventions is that they must claim inventions that are non-obvious in view of everything that preceded them. The standard for non-obviousness is murky, even to a patent attorney, examiner, or Supreme Court justice. The only sure bet is that ‘obvious’ in the world of patent law does not mean the same as ‘obvious’ in everyday speech. There are many ways to consider patent-related obviousness, and the best advice I can give is to enlist the help of a patent attorney in making such determinations. I have seen patents granted and enforced that to a layperson seem to be claiming trivial inventions. And I have seen patent examiners hesitate to grant patents for seemingly game-changing advances.
AS: Can I patent an idea?
JB: All patents are to ideas. Utility patents are the type of patent that most people think of, in which the invention is an idea you can articulate in words. Every utility patent ends with numbered sentences starting with the words “I claim” or “We claim” that are the ‘claims’ defining the invention – much like the plot lines on a deed establish the bounds of a real property right. The idea expressed in those sentences is what is being protected. A law professor once encouraged me to think of patents this way: every utility patent claim can be boiled down, essentially, to the statement of the realization of a cause and effect, like “if I do X, I get Y.” Such an idea may enable countless embodiments, or examples, in the form of widgets, or methods of making or using widgets, for example.
AS: Once my patent is issued in the USA, does it protect me in China or any other country?
JB: Patents are issued by sovereign governments and are only enforceable with respect to acts occurring within their territory. So no, a US patent is not enforceable in China. Some countries have banded together to share patent office duties, such that their combined organization issues patents that may then be validated in the individual countries in order to be locally enforceable. The European Patent Convention, for example, established the European Patent Office that issues patents that may be validated in various European countries. If such a patent is not timely validated anywhere, it is of no commercial significance.
AS: I always see “Patent Pending.” What does that mean?
JB: ‘Patent Pending’ simply means that you have applied for a patent. The value of such a mark is merely as a warning to would-be infringers, that if you do get a patent they may be forced to shift course. A pending patent application is not enforceable.
Topics: Intellectual Property, Inventors/Inventions, Legal, Patents | 1 Comment »
Castings – Part 2: An Introduction
By Mark L. Casey | September 29, 2011
In a previous article we briefly introduced three casting approaches, each with its own application. In this article we will explore cast iron, miniature zinc, and brass casting.
Cast Iron
Cast iron is an alloy of carbon, iron, and other elements. It can be cast into a soft and strong iron, or into a hard and brittle iron, depending on the exact “recipe” and method used.
Here is a video on the casting of cookware at Le Creuset:
Miniature Zinc
Miniature zinc casting differs from conventional zinc casting in several ways. First of all, the tool used in miniature zinc casting is a four-slide tool that is considerably less expensive than conventional die cast tooling.
In addition, miniature zinc parts can hold precise tolerances. For example, it is not uncommon for parts to exceed standard linear dimensional tolerances of +/- .002″ and precision linear tolerances of +/- .0015″. Parts can also be die cast with thin walls down to 0.020″ in. with tolerances as tight as +/-0.001″ in.
For an example of the kinds of machines used in four-slide casting, check out this link:
Brass Casting
Like the casting of other alloys, molten brass is poured into a mold for formation. After the part is removed from the mold, a variety of finishing operations may be used. Here is a YouTube video of brass valves being created:
Topics: Brass Casting, Cast Iron, Miniature Zinc | No Comments »
Die Casting Resource
By Mark L. Casey | April 27, 2011
Part I of our series on castings can be found here. Part II of our series will be postedsoon, but if you are interested in exploring die casting further, I want to recommend the excellent website of the North American Die Casting Association (NADCA).
This helpful resource not only provides a good introduction to the basics of die casting, it also provides a lot of technical information for those actively considering die casting or designing parts for die casting.
Topics: Design, Die Casting, Manufacturing, Supply Chain Management | No Comments »