The True Cost of a Concept Model

Concept modeling equipment creates physical models automatically from a CAD file. Concept modeling systems deliver designers and engineers physical prototypes that they can hold in their hand, which improves visualization and ergonomic study as compared to a standard paper printout. Concept models also are often used to enhance communication between the decision makers in design, engineering, marketing and manufacturing.

As industry pushes to reduce time-to-market for new products, there is increased appreciation for the value of physical prototypes throughout the design process. Companies are reducing the time and cost of bringing new products to market by using more concept models earlier on in the design cycle - increasing the number of design iterations. Just as computers have increased our use of paper, 3-D CAD and concept modelers have increased our use of physical prototypes. Nobody thinks twice about filling his or her printer with a new ream of paper, but should he or she be more careful about refilling the concept modeler with material? It is believed that the cost of concept modeling is very low, but is this correct?

Concept Modeling Vs. RP

These advantages make models more accessible to the design engineer, providing him or her with the freedom to make more parts and more iterations at the earliest stages of the design process.

Before investigating the cost of modeling, the advantages of concept modeling must be reviewed. All of the systems currently on the market use safe materials that can be handled in an office environment. The systems are quiet, easy-to-use and have no unpleasant odor. These are all important factors that distinguish concept modeling from high-end rapid prototyping, which belongs in a lab or shop environment.

While concept modeling systems are generally faster than rapid prototyping and traditional model making, their relative speed varies dramatically. In fact, the fastest concept modeling system can make parts up to 10 times faster than the slowest system. To the designer this is the difference between waiting an hour to hold his cell phone model (see Photo 1) and waiting overnight. A designer may be willing to take a break while the part is printing, but he or she will probably not be willing to stop all design until the following work day.

Because concept modeling is specifically focused on making models more accessible to the designer, speed is critical and how speed translates into throughput must be understood. In other words, faster systems make more parts, which means lower depreciation cost per part.

Cost Breakdown of a Concept Model

Capital Cost
The capital cost of the different concept modeling technologies is in the $50,000 to $60,000 range - making it substantially more affordable than high-end rapid prototyping. While the initial outlay is similar among technologies, the actual depreciation per part is substantially different because depreciation cost depends on throughput - the faster the machine, the higher the throughput, the more parts per unit of time; therefore the lower the depreciation per part.

Materials
Materials include all consumables required to run the equipment - such as build material, support material, waste material and replacement print heads. Build material costs vary by a factor of 10 times. So, a typical hand-held model such as the cell phone could use between $1 and $10 of materials. Certain technologies require support structures, which add to the material usage. Other technologies expend a small amount of material waste during the process. Finally, all of the technologies use some sort of print head or equivalent dispensing device. This needs to be replaced at certain intervals.

Training
All concept modelers are fairly easy to use, so the amount of training is minimal. This is, again, in contrast to some of the high-end rapid prototyping systems, which require extensive training and expertise in order to obtain satisfactory results. Many companies put their concept modelers in a central location where each designer in the group may submit his or her own files for printing - allowing use without a designated operator, which helps dramatically reduce the overall cost of ownership.

Labor
To properly account for cost of ownership, however, all of the labor costs should be included. Typically, the user would import his or her STL file into the system software, and then choose to rotate, scale or copy the part. This can take as little as a minute or as long as a few minutes, but generally less than five to 10 minutes. Then the file is sent to the printer. When printing is complete, the part must be removed. If there are support structures, these must be cut out from the part. Some technologies allow for post-processing in order to achieve a part with particular material properties.

Overall Cost

How much will this cost vary by technology? As discussed previously, depreciation on other equipment can be higher, depending upon the speed/throughput of the equipment. Also, the cost of build material, supports and replacement print heads may be higher as well.

Nevertheless, concept modelers can be operated in an office environment with little training or user involvement; they get the model into the designer's hands in a short amount of time because they are located right next to the designer and because of the inherent technologies used; and finally, they are very inexpensive.

In the end, the designer needs the freedom to make as many parts as will be useful for communication, collaboration and improved creativity. At sites where concept modeling is being used successfully, there are as many models in the trash as there are on the table. That's only possible because the true cost of concept modeling is approaching the cost of a cup of coffee.