Harvest Technologies Provides Rapid Prototyping - Materials









  1. What is rapid prototyping (RP)?
  2. What is rapid tooling (RT)?
  3. Where can I get more information about RP and RT?
  4. How do I get a quotation from you?
  5. How much does RP and RT cost?
  6. What are your lead-times?
  7. Why does pricing vary between service providers?
  8. What file format is needed to build a part or tooling?
  9. How do I send electronic data files to you?
10. How do I output STL files from my CAD software?
11. Will my design and intellectual property be secure?
12. What industries and applications do you serve?


  1. What technologies and processes do you offer?
  2. What materials do you offer?
  3. Which process e(s) and material(s) should I use?
  4. What are SLA and SLS and how do they work?
  5. How large or small of a part or feature can you build?
  6. What is the dimensional accuracy of SLA & SLS?
  7. What is rapid tooling (RT)?
  8. How do you make metal RP parts and tooling inserts?
  9. How durable and functional are RP materials?
10. Can these materials be used for end-use parts?
11. Can RP parts function in waterflow and airflow
      testing and are they resistant to solvents?
12. Can RP parts have functional living hinges?
13. How smooth of a surface finish can you provide?
14. Can you make parts in different colors?
15. What RP materials have high heat tolerance?
16. Are there are any non-toxic RP materials that can be
     sterilized for medical use?

1. What technologies and processes are available at Harvest Technologies? Many processes are available and in development. Some of the common direct-use technologies are SLS (Selective Laser Sintering), SLA (Stereolithography), CNC high-speed machining, FDM (Fused Deposition Modeling), Thermojet, LOM (Laminated Object Manufacturing), 3D Printing (Z Printing). Some widely used indirect processes are RTV tooling & urethane casting, metal casting, sheet metal fabrication.

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2. What materials are available at Harvest Technologies? Many materials are available, each with different properties and suitability to particular applications such as concept models, functional prototypes, presentation models, casting patterns and end-use parts. They vary greatly in strength, durability, rigidity, flexibility, fine detail, optical clarity and surface finish. Some of the rapid prototype materials that are currently available are epoxy, nylon, ABS, polycarbonate, polypropylene, steel/bronze and wax. You can access information about many of the commonly used RP materials at http://www.harvest-tech.com/materials.html.

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3. Which process(es) and material(s) should I use for my project? Each process is well-suited to some applications and not for others. You should choose the process(es) and material(s) that best meet your needs for dimensional tolerancing, durability, rigidity, flexibility, temperature tolerance, feature detail, surface finish and price for each project. Your priorities for performance and aesthetics should dictate the selection, not a service provider's desire to maximize their profitability. Assistance from a professional RP/RT expert with your best interest at heart can be very valuable.

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4. What are SLA and SLS and how do they work? These rapid prototyping technologies each "grow" 3d objects-prototypes, patterns, parts and tooling- layer by layer. In SLA a laser photocures epoxy resin and in SLS a laser sinters (fuses) thermoplastic powders to form an object.

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5. How large or small of a part or feature can you build? There are a variety of machines with different platform sizes in both of these technologies. SLA build envelopes are as large as 20X x 20Y x 23.62Z and SLS as large as 13X x 15Y x 18Z. Parts larger than this are commonly built by assembling and fusing multiple sections together.

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6. What is the dimensional accuracy of SLA & SLS? Dimensional accuracy varies among different RP/RT processes and materials. General tolerancing, however, for SLA and SLS is +/- .3% (.003 in/in) overall, with a minimum of +/- .005" on features and parts less than 1.75" in size. Upon request, however, tolerancing can usually be "dialed in" for tighter point-to-point tolerancing by modifying build orientation and/or beam offset parameters, or by building an object multiple times.

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7. What is rapid tooling? Rapid tooling is a blanket term that includes many different methods and processes for creating tooling and molding inserts in less time than conventional tooling. Usually rapid tooling is created for limited-run production quantities (1 to 100,000 in most cases) and is made using rapid prototyping and/or high-speed machining apparatus.

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8. How do you make metal RP parts and tooling inserts? An SLS metal part is made as follows: (A) grow a "green part" on the machine by fusing powdered steel particles with a binder material, (B) in a furnace cycle the binder is burned away and molten bronze wicks into the resulting pores forming a dense steel/bronze object. Most other metal parts are created by casting in temporary tooling created from a pattern master made on a rapid prototyping apparatus, or by machining ("hogging out") objects from a block of bar stock.

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9. How durable and functional are RP materials? RP materials range from very durable and fully functional to weak and brittle. Many SLS, CNC machined and cast plastics and metals are comparable to or equal to production materials in strength and functionality. The more fragile materials are more commonly used as static concept models or consumable patterns for casting.

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10. Can these materials be used for end-use parts? Yes and this is becoming more common. Typically small complex parts that don't have stringent cosmetic and/or dimensional tolerancing requirements, as well as parts that are highly difficult or impossible to tool conventionally are the best candidates for rapid manufacturing. Normally this is cost-effective for quantities of less than 1000.

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11. Can RP parts function in waterflow and airflow testing and are they resistant to solvents? Several of the RP materials can be used for waterflow and airflow testing without leaking. Some of the materials must be infiltrated or coated to achieve this and some are classified as solvent-resistant. Of course the specific solvents and time of exposure are key to a material's performance.

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12. Can RP parts have functional living hinges? SLS DuraForm PA and fine nylon, as well as the elastomeric Somos 201, can flex enough to function as a living hinge. Our technical staff has also developed techniques for improving the flexibility and durability of these materials beyond the norm. Some hinge geometries do better than others. Crimped hinges that concentrate stress in a small area tend to not do as well. Other RP materials are seldom, if ever, suitable for living hinge applications.

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13. How smooth of a surface finish can you provide? Almost all RP materials can have surface finish and cosmetic improvements made to them. SLA in particular, but SLS as well, can be sanded, filled and painted to look like injection molded plastic. Even texturing can be applied if time and budget allows. Most parts, however, do not require high level finishing, and are simply sanded and bead blasted. This creates and nice surface finish that is excellent for engineering purposes.

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14. Can you make parts in different colors? Most RP technologies do not allow for much, if any, color options in the actual building process. However, the parts can usually be dyed or painted, even color-matched in some cases, to a customer's specifications.

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15. What RP materials have high heat tolerance? Most RP plastics with higher heat tolerance are from the SLS and CNC technologies. SLS plastics have a melting point of 184 C (365 F) or more, and Ultem, an amorphous polymer, has a Tg-Glass Transition temperature of 215 C (419 F). There are some high-temp SLA resins and cast epoxies, but they tend to be brittle. We currently have a high-temp ceramic SLS material that we are experimenting with as well.

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16. Are there any non-toxic RP materials that can be sterilized for medical use? SLS DuraForm PA can be sterilized via autoclave and has received USP level VI certification for brief in-vivo exposure while serving as surgical devices. There are also some cast urethanes that are FDA approved. Many medical devices are also produced from rapid tooling.

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1. What is rapid prototyping (RP)? Rapid Prototyping (RP) has been defined many ways, but in general it is using a technological process to produce complex 3d objects in a short period of time--usually days rather than weeks. Most RP machines create 3d geometries by growing them layer-by-layer, but high-speed CNC machining--a deductive "hog out" process--also meets this criteria.

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2. What is rapid tooling (RT)? Rapid Tooling (RT), is general terminology for using a technological process to rapidly produce mold inserts for injection molding of plastics and casting of metals. Most rapid tooling is created in 2-4 weeks rather than several weeks, and is best-suited to limited run quantities of 1 to 100,000.

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3. Where can I get more information about RP and RT? There is a fair amount of information about RP & RT on our website, including PDF files at http://www.harvest-tech.com/materials.html. We welcome your calls and will gladly offer assistance in answering your questions and providing extensive data and samples. If we don't have an answer readily available, we can usually get one or provide you with a referral in a short time.

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4. How do I get a quotation from you? To provide a solid and accurate quotation we need to have STL files for all parts that are to be built, detailed information about the performance requirements of the parts and a good understanding of your expectations. Although we don't prefer to give loose estimates from napkin sketches, we sometimes can give you a ballpark idea of what to expect based on drawings.

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5. How much does rapid prototyping and rapid tooling cost? Unlike commodity goods and services RP and RT pricing cannot be factored by size, weight or billable hours Most layer-additive RP processes factor a combination of machine hours, material consumption and post-processing labor to quote production of a 3D object, be it part, pattern or tooling. The greatest economy is found in building batches of parts rather than one at a time. Many times it doesn't cost a lot more to produce several parts than just one. CNC machining quotes are primarily based on programming time, part complexity, build time, materials and post-processing labor.

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6. What are your lead-times? Most SLS and SLA jobs are delivered within 4 working days, but quantity, size and post-processing can affect the lead-time. CNC machining, casting and rapid tooling usually takes around 10 days to 3 weeks for delivery of the first articles. We always strive to accommodate those who need an expedited delivery.

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7. Why does pricing vary from service provider to service provider? There are many variables in quoting RP and RT: technology, sizes of machines, build styles, materials, service levels, quality levels, etc. As a quality-focused service bureau, we have been pricing our parts the same since the mid 90's when we started. Our customers appreciate this consistency and the fact that we don't raise prices when we're busy, or drop them when we're slow. We strive to provide our customers with the best "bang for the buck" value, and are willing to work with them to meet their objectives without breaking the bank.

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8. What file format is needed to build a part or tooling? Generally STL is the format required to build a rapid prototype and IGS is the preferred format for CNC machining. Most modern CAD software allows the user to output these formats. If you are unable to do so, we can assist you either with in-house translation software, or by outsourcing from a CAD service provider.

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9. How do I send electronic data files to you? The most commonly used methods of sending data to us are as follows: - E-mail (harvest@harvest-tech.com) - FTP (Browser: ftp://ftp.harvest-tech.com/incoming/) or (FTP software: ftp.harvest-tech.com/incoming).

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10. How do I output STL files from my CAD software? There are many CAD software programs these days and each one has its own specific way to output STL files. It is essential that you select high resolution settings when outputting STL files so the RP machines will build models that properly produce the geometries you desire. If you are unable to output an STL file from your software, seek assistance from your CAD software vendor or we can assist you in outsourcing CAD services from one of our vendors.

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11. How can I be sure that my design and intellectual property is secure with you? Because we daily work with cutting-edge designs and confidential data, most of which is not fully protected by law, we have to operate in a secure and restrictive manner. We are willing to sign a non-discloser agreement (NDA) and/or no-compete documents when required by customers. We operate with the understanding that your trust and confidence must be assured for us to be in business.

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12. What industries and applications does Harvest Technologies serve? You name it! Although we have made prototypes, patterns, presentation models and production components for dozens of industries, we mostly service the following ones: design & engineering, R & D, consumer products, electronics, aerospace, automotive, robotics, appliances, telecommunications, orthopedics, healthcare, dental, foundry, oil & gas, petrochemical, toys and plastics.

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