The article was authored by Terry Wohlers for Time-Compression Technologies. 
It was published in a special supplement with the November/December 2005 issue. 

By Terry Wohlers

Locating the right rapid product development service provider can be a challenge. You would expect it to be a simple and straightforward task—and it is for some—but for others, it can become downright difficult.

Hundreds of service providers, also referred to as service bureaus, are in operation around the world. The services offered by these companies, mostly small organizations, are wide ranging. Many offer modeling and prototyping services for design and manufacturing companies in automotive, aerospace and defense, consumer electronics, industrial machinery, medical, and other industries. The services can range from offering stereolithography parts and CNC machining to laser scanning for reverse engineering and producing urethane castings and plastic injection molded parts.

The problem with identifying a service provider can be twofold. First, you must fully understand the needs that you have and know how to accurately communicate them to others. Some entrepreneurs and startup companies have difficulty with this because they have little experience. The second is having sufficient knowledge about the materials, processes, and skills required to do the work, such as producing prototype parts. They are not sure where to turn, and when they do, the communication is weak due to their lack of understanding and experience.

Identify Your Needs
The first step is to articulate what it is you need. If a job requires design work, you will need to indicate specifically what you mean by that. For example, if you are working on a plastic enclosure for a handheld electronic product, you will want to prepare sketches and written requirements. If you are unable to do this, you will have a difficult time communicating your needs to a service provider. If a description of the product is not yet complete, that's okay. The service provider can work with you to answer questions and describe the product as fully as possible. Costs can be at their lowest when you are fully prepared, organized, and can clearly communicate the detailed job requirements.

If a part or assembly has already been designed and is available in the form of a CAD model, seeking one or more prototypes is usually much less involved. If the design is documented as a set of drawings and specifications, but not as a CAD solid model, most service providers will accept them, but expect to pay a premium to have them converted to a solid model. It requires a CAD expert to create the design, usually from scratch, in SolidWorks, Inventor, ProEngineer, or another CAD software product. The work can take days of time and cost more than the prototypes you are seeking.

If you are not familiar with the materials and processes that are commonly used by companies in the prototyping business, asking the right questions can be difficult. It would be somewhat like trying to buy a new computer without knowing the difference between a pixel and megabyte. It turns into a frustrating and unproductive experience. You can usually learn a fair amount by visiting websites to see what these companies offer. At minimum, it is helpful to learn the basics of stereolithography and laser sintering, and the materials they handle, because they are two of the most popular processes used by service providers. It is also helpful to understand secondary processes such as urethane casting from silicone rubber molds, if you need several plastic prototypes. If you need metal parts, a basic understanding of metal casting is beneficial.

Individuals and startup companies that are developing a new product often seek advice on where to start. They will contact a service provider, sometimes at random, or someone such as myself. They usually know a lot about a specific industry and the product they are developing, but know little about additive technologies for rapid prototyping or secondary processes such as tool making and molding and casting. Much of the time, they need basic guidance on where to find the right service provider to help them finish a design and produce prototypes for form, fit, and functional testing.

After communicating the important elements of a job, it can be best to step back and permit the service provider to do its work. It is okay to stay in touch during the design process, but try not to get in the way and become burdensome. If you drive every design detail, the service provider will become frustrated, it could take longer, and the price will likely increase. Some inventors are notorious at not letting go.

Where to Find These Companies
Several sources are available to help you find the right service provider. This supplement is aimed at providing assistance of this type, so it will likely help you as a starting point. Another resource is the Service Providers page at wohlersassociates.com. It lists many companies in this business, along with a brief description and a link to their websites. Castle Island Company currently provides the most comprehensive service provider directory. Google the company to find it on the web and then click the Service Bureaus button near the top of the home page.

Another source of information is the Rapid Technologies & Additive Manufacturing (RTAM) Community of the Society of Manufacturing Engineers (SME). SME's Rapid Prototyping Association was transformed into RTAM a couple years ago when the society reorganized. Go to www.sme.org/rtam to join one of several discussion groups (called Tech Groups) at no cost. Members in these groups have expertise in many areas of product development and manufacturing.

One more option is to post questions on the Rapid Prototyping Mail List (rp-ml). It is an email list server with subscribers from around the world. To subscribe (it's free), send an e-mail message to majordomo@rapid.lpt.fi. Enter "subscribe rp-ml" in the body of the message. The subject line is ignored. Automatically, you will receive all messages sent to the list. After you have subscribed, send questions and comments to rp-ml@rapid.lpt.fi, but note that several hundred individuals and companies will receive them. It's a good practice to keep the message brief and to the point. To unsubscribe, send an e-mail to majordomo@rapid.lpt.fi with "unsubscribe rp-ml" in the body of the message.

It can be helpful to identify a company that is within driving distance, especially if the job involves design work. With the simple production of parts, it is less important. By meeting with the company representatives in person, it becomes easier to decide whether you want to do business together.

Quality of Service
Most companies that have stood the test of time and have been in business for years provide solid services, although there are exceptions. If you can, talk with a neutral party that has firsthand experience with the company of interest. Ask for references. There is really no substitute to word-of-mouth advice.

New companies can also offer quality services and good value, but you need to learn as much as you can about them, the same as when buying any product or service from a new company.

Most companies will provide an estimate of cost within a couple days and some will do it even sooner. The more involved jobs take longer to fully understand and quote, so take this into account when waiting for a written response. A growing number of service providers offer web-based interfaces for sending a request for quote. A few even provide real-time quoting, so you can determine the exact cost in minutes. Examples are Mydea Technologies, Quickparts, and Xpress3D. Of the three, Mydea Technologies is the only one that does not require you to register or download software to take advantage of the quick quoting capabilities.

Timing
From the time you give the service provider the green light on a job to the time of completion can vary greatly. The biggest variables are the amount of design and engineering work involved, if any, and the number and types of parts you need. If you provide a good STL file, and you need only one or two parts, you may receive the order within a couple days. (STL is the de facto standard file format required by most additive fabrication systems. Most CAD systems export STL files.) If the project requires parts with a high quality surface finish and paint, it may take another day or two or longer. If the service provider is backed up with work, you may experience a delay.

If you need multiple copies of a part or assembly in a special material that is not available from stereolithography, laser sintering, fused deposition modeling, or another additive process, your job may require tooling. Urethane parts from a rubber mold are acceptable for many prototyping applications, so you may want to consider this option. Creating the rubber mold and molded parts can take a week or much longer, depending on the size, complexity, and number of pieces you need.

If your project requires injection-molded parts from a metal tool, such as aluminum, it can take longer and cost more. However, you can get thousands of parts from the mold in a wide range of popular thermoplastics. Lead times vary greatly. Small, simple tools can be finished in under a week, while larger, complex molds can take several weeks. Protomold is a company that is capable of delivering small injection molded parts in as few as three days.

The need for metals parts requires other considerations. Options are typically CNC machining, as well as processes such as investment casting. Lead times vary widely depending on the size and quantity. Plan on a couple weeks minimum, although there are special cases when it has been done more quickly. Some additive processes, such as laser melting, are being used to produce metal prototypes. The accuracy and surface finish is typically similar to a sand cast part, so mating surfaces and critical dimensions require finish machining, similar to metal castings.

Ongoing Work
After building a trusting relationship with a service provider, jobs are usually started with much less effort and overhead. After several jobs under your belt with the same company, it's not unusual to send CAD data and initiate a job without requesting a quote. You know that the company will treat you fairly on price. The service provider knows that if it does not, you may not return. This type of working relationship enables you to move quickly on a project without waiting for something in writing. Also, the service provider trusts that it will get paid and will forego the need for a purchase order or some other promise of payment. Not all of them work this way, but some do.

When it's all said and done, the experience of working with a service provider comes down to the people that make up the company. If the managers and other employees at the service provider are honest and likeable, the customer will return with more work, assuming that they are receiving quality work at a fair price. Sometimes, these relationships are so strong that if your primary contact leaves the company, you feel cut off and immediately begin to consider other service providers. It is often the relationships that creates the loyalty, not the companies themselves. It is somewhat like the comfort you develop with your travel agent or dentist.

Finding the right service provider can be easy or difficult, depending on your specific needs, background, and experience. If you are new to rapid prototyping and manufacturing processes, invest some time—even a couple hours—to understand some of the most popular materials and processes. Then, make contact with one or more of the service providers to explore options. They are more than happy to help.

Industry consultant, analyst and speaker Terry Wohlers is principal consultant and president of Wohlers Associates, Inc. (Fort Collins, CO). For more information visit http://wohlersassociates.com.