High-Resolution Material Increases Prototype Quality

October 1, 2002

6 Min Read
High-Resolution Material Increases Prototype Quality

Originally Published MPMN October 2002

EQUIPMENT NEWS: Radio Prototyping

High-Resolution Material Increases Prototype Quality

A new modeling material from Stratasys Inc. allows for the production of prototypes with tight diameter tolerances.

Distributed by Stratasys Inc., a high-resolution molding material increases the quality of fused deposition models. "The fused deposition modeling process is dependent on fine control of the modeling material to achieve accuracy," explains materials development director Bill Priedeman. "Our new molding material is constructed using more stringent manufacturing controls, allowing it to produce models with tighter diameter tolerances."

Particularly suited for the production of small and thin-walled models with fine features, the material is compatible with the company's FDM Quantum, Maxum, Titan, 1650, 2000, 3000, and 8000 prototyping machines. Previous material formulations will no longer be available.

Stratasys also recently began shipping the 3.3 version of its Insight software as an upgrade for all users with service agreements. Required for performing 5-mil slicing, the update allows for the optimization of the modeling envelope to incorporate more parts. The software also includes editing tools that increase build control, and seam control enhancements that improve surface finish.

Stratasys Inc., 14950 Martin Dr., Eden Prairie, MN 55344.

Milling Machine Performs High-Speed Five-Axis Machining

Supplied by Mikron Bostomatic Corp., this milling machine features direct-drive rotational axes that achieve faster speeds than their mechanical counterparts.

Employing advances in direct-drive technology, a milling machine from Mikron Bostomatic Corp. achieves simultaneous five-axis machining at high speeds. "High-speed machining is nothing new to the rapid prototyping community," says sales and marketing vice president Mal Sudhakar. "Nor is five-axis machining, but the HSM 400 U miller may be the first unit that combines both of these traits in a single product."

According to Sudhakar, this breakthrough was enabled by constructing the unit's rotational axes with direct-drive instead of mechanical components. "With the previous mechanical design, these axes could only achieve a top speed of 20 to 30 rpm. The new axes can accelerate to 250 rpm, a speed that's 25 times that of some conventional rotary tables," he says.

Suited for wet or dry machining, the HSM 400 U miller is constructed with a patented polymer base to dampen vibrations and offer thermal stability. "The unit's base is 10 times as dampening as cast iron, allowing for smoother cutting and better accuracy with less tool wear," says Sudhakar. Other unit features include liquid-cooled spindle motors that achieve speeds up to 60,000 rpm, and a built-in laser measurement system that monitors tool radii and lengths to ensure long-term positioning accuracy.

To facilitate use, the HSM 400 U is equipped with a computer control system. This system is capable of displaying 3-D graphics and features a 1.5-gigabyte hard drive and an Ethernet port. In addition to prototyping applications, the milling machine can be used for standard production and features an integral workpiece changer to allow unmanned operation. A pallet magazine and changer are also included as standard features.

Mikron Bostomatic Corp., 125 Fortune Blvd., Milford, MA 01757.

Desktop Milling Machine Eliminates Secondary Operations

A desktop prototyping machine that is small and easy to move can mill objects on all four sides when equipped with an optional rotary axis. Despite its diminutive footprint, the Roland MDX-650 machine supplied by Gold International Machinery Corp. offers a work area that measures 19.7 x 14.2 x 17.7 in. The machine can be used to produce 3-D prototypes from aluminum, brass, copper, wax, wood, and ABS.

Using a subtractive prototyping method that minimizes costs and eliminates the need for secondary operations, the MDX-650 machine also ensures safe operation. The unit features an emergency stop switch that lets users rapidly shut down the machine when problems occur. An optional safety cover is available to make the cutting mechanism inaccessible during operation. This component can also prevent dust from exiting the machine, making it suitable for use in office environments.

The MDX-650 comes bundled with the Modela Cam software package for importing .dxf and .stl files from CAD/CAM software. The program also performs uniform 3-D scaling, selects milling direction, and automatically generates and displays the tool path. Cutting depths and speeds are controlled from a predefined material library or from user-defined specifications. Compatible with Windows 95 and higher operating systems, the software supports full four-axis indexing.

Gold International Machinery Corp., P.O. Box 998, Pawtucket, RI 02862.

Adapter Kits Simplify Connection Prototyping

An adapter kit can convert surface-mount components to through-hole devices.

Adapter kits from Accutek Microcircuit Corp. simplify the prototyping of medical electronics. Available in standard-pitch, fine-pitch, memory, and plastic-leaded-chip-carrier/pin-grid-array models, these kits contain a variety of chips used to convert surface-mount components to through-hole devices. "A lot of times, manufacturers can't find the specific adapter they need to create a prototype," says product manager Scott Cohen. "These kits allow them to build exactly what they want without leaving their laboratory." According to Cohen, companies have used these kits to build prototype CAT scan machines, brain-wave monitors, and respirator control units.

The adapter kits are available with a choice of solder-plated machined or solder-tinned flat-contact pins. Components with pin counts ranging from 4 to 48 are suited for connecting integrated-circuit packages to dual-in-line-package modules. The plastic-leaded-chip-carrier/pin-grid-array kit offers parts with pin counts of 20 to 100. All feature a FR4 substrate that is flame retardant and suited for replacing end-of-life through-hole integrated circuits.

Accutek Microcircuit Corp., 2 New Pasture Rd., Ste. 1, Newburyport, MA 01950.

Prototyping Machine Minimizes Moving Parts to Increase Dispensing Accuracy

The metering pumps in this rapid prototyping unit from Liquid Control Corp. are constructed without inlet check valves to offer a dispensing accuracy of +0.5%.

A rapid prototyping unit supplied by Liquid Control Corp. features positive-displacement piston metering pumps with only two moving parts to offer a dispensing accuracy of ±0.5%. Suited for dispensing fast-curing polyurethanes, the pumps of the Posiratio Mini machine are constructed without the inlet check valves commonly found on other machines. "Essentially, this design change makes the Posiload pumps similar to large syringes," says fabrication business manager Jerry Drake. "And because there are fewer moving parts, there are fewer components that can block and decrease accuracy."

Another simplifying feature of the Posiratio Mini machine is its use of Posimixer gravity-fed mixers. Eliminating the need for pressurized tanks, these disposable components keep reactive materials separate until they are applied into the machine. "These mixers are motionless, relying on the velocity of the materials as they pass through the machine to ensure a proper mix," explains Drake. "They don't have any moving parts so there's less to go wrong here as well, and they're disposable so there's no need for solvent purging."

Equipped with a 5- or 7.5-L tank, the pneumatic Posiratio Mini machine allows the application of machine- or operator-controlled shot sizes of 1 to 25 cm3. The unit accommodates material viscosities that range from those of water to heavy paste and features flow rates up to 10 lb/min. Offered with an optional touch screen, the machine is controlled via a programmable logic circuit that simplifies use.

Liquid Control Corp., 8400 Port Jackson Ave. N.W., North Canton, OH 44720.

Copyright ©2002 Medical Product Manufacturing News

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