A better way to Cost-Out Designs

April 18, 2002
New costestimating programs may change how manufacturers work with suppliers.

DFM Concurrent Costing 1.1 guides designers through an analysis of the primary cost drivers associated with manufacturing. This view shows the starting sequence of a typical design analysis. The Process and Material Selection window is open on top. A solid model of the part appears in SolidView/Pro. The user selects a material and manufacturing process for initial estimates. The middle window shows basic information and dimensions for an ABS injection-molded part. Compatible material and process selections are color-coded to help to the user.

In another Concurrent Costing analysis for a brass fitting, the software generates costversus-quantity curves, and costs for different casting methods.

The process layout was generated for laser cutting by MSE from Micro Estimating Systems Inc. (www.microest.com) Such information can help designers guide their work, but it's more useful for manufacturers.

The table in Bom.com shows costs for an assembly listed from the most expensive component down. One tactic for cost reductions is to rework the most expensive components. The software includes a purchasing history showing products that may come from multiple suppliers. Users can also get quotes and purchase histories for the cost rollups calculated by the software.

Quickparts.com generates binding quotes, not just estimates, for rapid-prototype parts. Users can upload STL files to the site and identify a material and quantity after registering. Available RP methods include SLA, SLS, FDM, and wax patterns. The online service returns firm quotes, often within seconds. A 16-in. Olympic torch built in a stereolithography machine with a standard finish will cost $1,130. Algorithms in the company's database calculate the model's surface, volume, and material, along with production parameters to generate quotes. Changing parameters updates the quote. There is no charge for the service to users and it's available 24/7. When users accept a quote, the company builds and ships the part. The company also quotes sheet-metal and cast-metal parts, but those quotes are not instantaneous.

The torch handle sent to Quickparts for a sample quote is about 16-in. long and 3-in. diameter.

An input screen from the Costimator demonstration (www.costimatoronline.com) shows the Process list. It grows as users identify operations, such as machine and inspect parts. The demo ends with detailed times for each step in the process plan. The site includes an OnLine Guide and .pdf file of what to expect in the demonstration.

Most engineers have heard the old saw that 70% of product cost is nailed down in the design stage. But many designers argue this is useless information because they have little idea of all the costs they are nailing down. Companies rarely get a clear cost picture until the product starts shipping. It doesn't have to be this way.

Take for example, a small EastCoast manufacturer that was planning to produce 30,000 oven brackets. At this volume, they were unsure whether to go with a stamped sheet-metal design to take advantage of inexpensive tooling, or design the bracket for powder metal and use material more efficiently. The manufacturer turned to DFM Concurrent Costing software to examine the trade-offs. A 10-min analysis showed the stamped design cost 10% less.

But powder metal became less expensive if they produced 10,000 more brackets. Information of this sort let the bracket maker plan a more profitable strategy.

Unfortunately, the anecdote is an exception, not the rule. So how can engineers get a fix on the cost of a creation when it's only partially finished?

A few software developers are chipping away at the problem with programs intended for design departments. The design-for-manufacturing program mentioned above lets designers compare costs for parts made by a range of different manufacturing processes, including casting, injection molding, milling, and sheet metal. Another program, an online bill-of-material, lets managers track parts — purchased and built — for a better idea of the final part cost before production begins.

These and other programs are changing the way design companies work with suppliers.

The software used to estimate bracket costs is from developer Boothroyd-Dewhurst Inc., Newport, R.I., (www.dfma.com) and in fact, targets designers. The company has produced design-for-analysis-and-manufacturing software for years, but only recently compiled all its costing programs into one. Concurrent Costing 1.1 is more automated now, so users need only describe parts and identify a process, such as milling or casting. "Concurrent Costing is an analysis tool for design," says John Gilligan, Boothroyd-Dewhurst president. "After opening a CAD file in the costing program, it looks for part dimensions, weight, volume, the number of surfaces, and other measurements before generating a cost." Users can rerun the analysis with different materials and processes to find those most appropriate or the least expensive. The software currently works with Pro/E, Catia, Unigraphics, I-DEAS, AutoCAD, and SolidWorks.

Those using other CAD packages can turn to SolidView/Pro 3-D, from Solid Concepts, Valencia, Calif. It lets Concurrent Costing read models and geometry in nonCAD 3D formats such as STL, DXF, OBJ, IGES, and VRML. The costing software can still examine the geometry to find values for surface area and volumes, and then generate cost estimates.

"The software provides a quick estimate that can be refined without inputting information several times," says Gilligan. The software asks for details such as shapes, expected life, and wall thicknesses. The estimate is refined as more geometry takes shape.

Gilligan says cost information is changing the way engineering departments work with suppliers. "For instance, instead of beating up suppliers for lower costs, the estimates developed without bias can let the parties work to each other's benefit."

One estimating program improves its accuracy by recognizing features in models rather than relying on the user to describe them. Developer Micro Estimating Systems Inc., New Berlin, Wis., (www.microest.com) has built what it calls Automatic Feature Recognition Estimating into their Machine Shop Estimating software.

So far, it only works for sheet-metal designs that will be cut in turret punch presses. "The system interrogate entities selected by the user and interprets the elements, whether circles, squares, rectangles, lines, or complex shapes," says Charles Beyer, president of the company. "It feeds this information to the estimating algorithms in the form of shapes, lengths, widths, and distances between features." This used to be a manual operation.

The MSE software assists other ways. For instance, Parker Hannifin Gas Turbine Facility, Clyde, N.Y., builds components for hot sections in jet engines. To keep production costs low, James Tormey, a manufacturing engineer with the company, generates estimates for several different manufacturing methods and for up to seven quantities. "We consider multiple options for different machines and methods," he says. "So the costs may suggest it's cheaper to produce a particular part on a turret lathe and drill press, rather than entirely on a CNC machine." Tormey often takes this data back to the designers to see if materials that are easier to run are acceptable.

The software is useful in other ways as well. For example, Tormey frequently has to find suppliers to make prototypes. "When something is needed quickly, I'll take a detailed cost estimate to a supplier with the job offer. If they accept, I give them the shop routing for manufacturing the part and other information generated by the MSE software, such as the times, operations, and even the tool list." This information speeds up the shop work.

Several recent costing services have popped up online. They include bom.com and Costimator OnLine.

Bom.com (www.bom.com) was developed as a sophisticated bill-of-material system that is supposed to improve collaboration between clients and suppliers. It has grown into an adaptive database. It's also aimed at engineers and managers who track parts and costs in assemblies.

"As the BOM for a product comes together," says Michael Topolovac, CEO of Bom.com, "Managers can ask it questions, such as: What are the top ten most expensive components in the product?" Work can then focus on those components or subassemblies to trim costs. Having the dollar value available gives managers several avenues for cost reduction. For instance, should the cost of power supply seem out of line, the manufacturer can be contacted for a pricing update.

Bom can also identify all components sourced from a particular company. Such information might be a lever to argue for a price break. An upcoming release should let suppliers add or change component prices.

Costimator OnLine from MTISystems, West Springfield, Mass., provides costs for machined and fabricated parts. An online demo (www.costimatoronline.com) lets registered users try it out for several days. The demo requires users to first download a Citrix client for their computer, an operation that takes a minute or two.

Because the software is aimed more at manufacturers than designers, it demands more knowledge of how parts might be produced. But it is useful for getting a handle on approximate costs for different materials and production operations. For example, in the demo, users select a material, identify the stock, part sizes, and some of the detailed operations such as abrasive belt grinding and particular work centers. The software builds a production tree showing each step with details that can include inspections, packaging, and shipping. The final screen presents costs

for each operation, which could let designers zero in on high-cost operations, and then test methods that might produce parts less expensively. The software can be purchased for a company's estimating department or run online for about $250/month.

The range of capabilities sampled here shows there are several packages available for designers and manufacturers alike. Perhaps a glimpse of things to come can be seen in technology like PlanetCAD's DesignQA software.

Designers run the software several times in their work to spot flaws such as duplicate surfaces or where models deviate from a company's best design practices. Costing software working in a similar manner could read features from CAD models along with information such as surface finishes, tolerances, and material, and then generate detailed cost figures. It's not exactly in the offing, but it could happen.

Take a shot with this estimator

Developer David Kazmer says his design cost estimator provides good estimates of injectionmolded-part costs. Results compare well with public and proprietary programs.

An online estimator for injection molding www.ecs.umass.edu/mie/faculty/kazmer/imcost/imcost.html, was developed by David Kazmer, a professor with the University of Massachusetts. He developed it and put it online because he believes engineering research should culminate in something directly usable by industry.

It's about the easiest estimator to use. Select the material type, quantity, cavities per mold and a general estimate of part complexity along with general dimensions. The software responds with the four costs and processing details.

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