There are many factors that affect the production and delivery of stereolithography prototypes. Weather is one critical factor. These factors affect the stereolithography process:

• Humidity - SLA prototypes can absorb moisture
• Heat - SLA prototypes are more brittle when cold and softer when warm

While at ProtoCAM, stereolithography prototypes are made and packed in a controlled environment, so the prototypes do not experience weather extremes here. But they do have to be shipped to customers, so once they leave the ProtoCAM facility, they are exposed to other conditions.

In order properly protect prototypes during shipment, the following precautions are taken:

• Prototypes are properly cushioned in the shipping container, which also insulates the part from temperature extremes
• Support is provided in the container for the prototype if the shape of the part requires it
• The day of the week is considered for shipment - in hot weather, we might delay a Friday shipment until Monday so that the prototype is not exposed to long periods of heat while in transit

With ProtoCAM’s vast prototyping experience, even these seemingly minor details are considered to provide you with the best service and best results.

Request a quote for your next stereolithography prototype!

Labels: protocam, prototypes, rapid prototyping, stereolithography

ProtoCAM does most of its prototyping work using additive rapid prototyping technologies such as stereolithography (SLA), selective laser sintering (SLS) and 3D printing. Fused deposition modeling (FDM) is another additive rapid prototyping process that is used. With additive rapid prototyping, material is added on or built up in the creation process.

Subtractive prototyping is another way to create prototypes in which material is removed from a larger piece of material. Subtractive prototypes are typically created using more traditional manufacturing processes. These include standard machining process such as milling, turning/lathing or drilling, and more modern tools like CNC machining. So with subtractive prototyping, you might start with a block of metal or plastic and cut away material until the prototype part is created.

In rapid prototyping, there are advantages and disadvantages to any choice of technology. Subtractive prototyping is limited to relatively simple shapes - complex geometries are not possible. The material must be readily available in the size and shape needed. And subtractive RP usually takes longer. Its main advantage is that is made in the final production material.

So if time, design complexities and materials are critical, additive rapid prototyping is likely the best choice. Contact ProtoCAM for additive rapid prototyping services.

Labels: rapid prototyping, rp technology

It seems to be a daily question when customers call ProtoCAM for a quote: “How do you price a stereolithography prototype?” or “What are my options for reducing the cost of my part?”

Stereolithography parts are priced using 5 criteria (in order of importance):

1. Overall height of the part - Most parts are built using a .004” layer thickness. The exception is a high resolution build which uses .002” layer thickness. The 3D file is “sliced” into layers and then traced and solidified layer by layer on the SLA machine. Consequently, a 6 inch part (1500 layers) will take longer to build than a 3 inch part (750 layers) and therefore, cost more.
2. Volume of the part - This relates to the number of cubic inches of material that will be needed to make the part. Again, the larger the part the greater the volume of material needed and the greater the cost.
3. Complexity of the part - When the part is finished on the SLA machine, it will require time to have the excess resin removed as well as having the support material removed. The prototype is then post cured in a UV oven and bead blasted to provide a consistent finish over the entire part.
4. Finish level of the part - ProtoCAM offers several levels of part finishing ranging from an economy “strip and ship” to a “presentation” level. Our standard level of finish requires the removal of supports with some light sanding on the support surfaces with an overall bead blast prior to shipping. See our Stereolithography Prototypes page to see our offerings of various finish levels.
5. Lead time of the part - ProtoCAM’s standard lead time is 2 days after receipt of order. Some parts, due to size, require a longer lead time. If you need your prototype part sooner, there is an additional charge to accomplish that requirement.

Understanding the above criteria can make the answer to the second question “What are my options to reduce the cost of my part” seem a lot easier.

Height of Part
Since the biggest contributor to cost is the overall height of the part, the simplest way is to either orient the part with a smaller z height or cut the part in half and allow us to glue it together prior to shipping.

Volume
Reducing the volume to cut the part cost can be accomplished by “hollowing” solid pieces or reducing wall thickness on thick walled parts.

Finishing
If a “presentation” level piece is needed, it can be the customer’s option to perform that work. An experienced customer knows that it can take several hours (or days) to completely sand a stereolithography part, but because of timing or cost the customer may choose to do that work themselves.

Lead Time
The easiest way to reduce part cost is to increase the lead time. If the customer doesn’t need the part within 2 days, increasing the lead time to 1 or 2 weeks will also cut the prototype cost.

Number of Prototypes Ordered
If multiple copies of the prototype may be needed, it is highly recommended to purchase those with the initial run of parts. Economies of scale come into play here and the greater the quantity ordered the smaller the per piece cost.

ProtoCAM will generally orient the part to give the customer the best quality within the shortest amount of time. But if other options need to be explored to meet scheduling or budget constraints, we recommend calling us at 1-800-408-9019. Just ask for the project manager that quoted your project (name can be found in the upper left hand portion of the quote) and we will be glad to explain options that are available to meet your requirements.

Ray Biery
ProtoCAM Managing Partner

Labels: prototypes, rapid prototyping, stereolithography

Hi, my name is Faye Stenack and I have been the office manager at ProtoCAM for four years. I remember the first time I walked in the front door at ProtoCAM and found myself totally amazed at the complexity and variety of parts that were produced on the stereolithography machines. I felt like I had just stepped into another world that I never knew existed. Instantly, I knew this was the right job for me and where I wanted to work every day...that has not changed. I am still excited to be a part of the ProtoCAM team. We all have the same objective which is to provide quality parts and service to our customers in a rapid fashion.

I recently had the opportunity to attend the MDM East 2008 Trade Show in New York City at the Jacob Javitz Center. I was astounded by all the different companies that exhibited and the products they displayed. It was quite an eye-opener and a wonderful experience. It was so nice to finally meet some of our existing customers that you usually only get to talk with via e-mail or on the telephone. The positive comments that were shared proved to me that we are doing a good job and listening to the needs of our customers and giving them the quality and service they deserve.

ProtoCAM is a very people-oriented environment and I would encourage you to give us a call or send us an e-mail with your concerns or requests. I feel confident you will become one of our satisfied and valued customers that keeps coming back project after project, too!

ProtoCAM will be exhibiting at Atlantic Design & Manufacturing tradeshow next week, June 3-5, 2008 at the Jacob K. Javits Convention Center, 655 W. 34th St. (West 34th Street at 11th Avenue), New York, NY.


ProtoCAM's booth is number 201 - please stop by and visit us there.

Click the coupon below to view important show information and register for a complimentary expo hall admission - a $55 savings.

When screwing your prototypes together, using the proper technique is critical. Tapping the hole is an option, but the threads can wear relatively quickly in certain prototyping materials. Using self tapping or thread forming screws should be avoided with most prototyping materials, because these fasteners can crack or damage the prototypes. Threaded brass inserts work well when the prototypes must be assembled and disassembled multiple times.

ProtoCAM can assist with the installation of threaded brass inserts into our stereolithography prototypes, as well as SLS nylon prototypes, Polyjet parts, and cast urethanes. There are two types of inserts that can be used in our prototypes, standard and expandable threaded brass inserts. Choosing the correct insert for your application is critical. Please make sure the holes are designed per the tables below.

Standard Inserts

The standard threaded brass inserts work well with all types of prototyping materials, especially SLA prototypes. The inserts are installed into the prototype with an adhesive. Keep in mind that these inserts are only held in by epoxy glue, and should not be used for high torque applications. Recommended minimum wall thickness around the insert is 0.060”. For high torque applications, it would be best to contact ProtoCAM's engineering staff for recommendations. See the chart for the design guidelines when using the standard threaded brass inserts.

Expandable Inserts

The expandable threaded brass inserts works great with durable prototyping materials, such as urethane castings. These inserts are pressed into an undersized hole. As the machine screw penetrates the insert, it expands slightly. This expansion allows the insert to bite into the sidewalls. Recommended minimum wall thickness around the insert is 1/2 the hole diameter, or a minimum of .060”. These inserts provide a slightly higher pull out force, when compared to the standard inserts. For high torque application, it would be best to contact ProtoCAM's engineering staff for recommendations. See the chart below for the design guidelines when using the expandable threaded brass inserts.

Ryan Schmidt
Engineering Manager
rschmidt@protocam.com

One question that I get asked on a regular basis is "How large a part can you build?" Rapid prototyping machines have a fixed size, and many of them have a relatively small area where they can build parts (their "build envelope"). Our largest machines, the SLA-7000s, have a build envelope of 20" x 20" x 23", but this doesn't limit the size of the parts we can deliver. By sectioning your CAD model into 20" x 20" chunks, we can build parts of any size.

When we receive a large part for quotation, we cut it into sections in a way that minimizes cost. The typical factors we consider are total height of the platen (if you don't know already, we use height and volume to estimate cost, and we adjust that based on part complexity), number of platens, and number of cuts. We then price it based on the machine's run time and finishing/gluing time, so you get a quote with the information you need to know -- how much it will cost you, and how quickly you can have it.

Once you give us the job, we go back and cut the part again, this time adding lap joints for strength. This step allows us to produce a part that is very strong along its seams, and that can be positioned back together accurately. For parts with complex cutting requirements, this step may be responsible, partly, for any additional lead time (beyond our typical 2-day turnaround) that you were quoted.

After the parts are cut in CAD, they are prepared for build in the 3D LightYear package, a proprietary software package built for stereolithography machines. This step comes up with the set of instructions that the SLA machine uses to build. (Conceptually very similar to the G-code used to run CNC machinery.)

Once finished, the parts are drained, removed from the perforated metal platen, separated from their supports, rinsed of excess resin, and cured in a UV oven. After this step, the lap joints are sanded so the parts can be fit together. Once the fit has been adjusted optimally, the parts are bonded with one or both of the glues that we've settled on using after years of experience. This leaves the seam with excess material and sometimes slight discoloration. The seam is then sanded until it is smooth to the touch. This process is repeated for each piece that needs to be glued together. Often times, our choice of glues leaves the seam stronger than the part.

With this proven process, we can deliver you prototypes of any size, from dashboards to wind tunnel models to tractor seats to chair backs. Large parts require extra care when shipping, but we have great experience doing that, from customers local to us in the Lehigh Valley to those on the other end of the country in California or Washington.

If you have any questions, call (610)261-9010 or leave a comment here on the blog.

Labels: CAD, cutting, large parts, prototypes