July 20, 1998

6 Min Read
Assembly options grow

Fastener improves low-ductile performance

Problem: In recent years, the use of die-cast magnesium in automotive, computer, and other applications has increased significantly. Unfortunately, fastening this material can be a challenge because of its low-ductile nature. For example, standard thread-forming fasteners, with a 60-degree flank angle, create excess debris. They can easily exceed the ductility limits of the material, causing damage to the formed threads.

Solution: The patented Mag-Form(TM) thread-forming fastener features a lobular configuration, wide-spaced thread design, and broad flank angle. These features help eliminate costly and time-consuming tapping operations, and form strong mating threads in low-ductile materials, says manufacturer Camcar Textron.

As the fastener is driven, the high-degree flank angle compresses the mating material, rather than roll-forming it. This action creates strong mating threads while minimizing debris generation and decreasing the potential for fracture of the application material. And, the formed mating threads allow multiple removals and reinsertions of the fastener.

Applications: Mag-Form fasteners are suited for use in a variety of automotive applications, including steering wheels, instrument panels, and powertrain components.

Weld system compensatesfor changes

Problem: Fluctuations in welding conditions, surface contamination, and changes in mechanical timing can interfere with effective welding.

Solution: The self-diagnostic Stud Welding System (SWS) monitors and compensates for such changes. It comprises a TMP Welder Control, a Stud Feeder, and a weld gun.

The TMP Weld Control switch-mode power supply provides timing and control functions for the system. A microprocessor performs thousands of finite electronic analyses, adjusting weld current, arc voltage, welding time, and stud-plunge timing to compensate for varying surface conditions such as oil, grease, and blemishes. Increases or decreases can be as much as 25% of weld parameter.

Wide ranges of weld parameter adjustments allow precise weld schedule control and tolerance monitoring with fault alert and out-of-parameter signaling capabilities. SWS software transmits fault signals to the weld controller after three consecutive parameter-tolerance violations at the same weld location. It then automatically replaces the welding tool without interrupting production.

Applications: The Stud Welding System is suited for heavy transportation, machinery, construction, and furniture applications; as well as the manufacture of electrical, electronic, and recreation equipment.

Threaded fastener delivers strong right angle in thin sheets

Problem: Thin panels make it difficult to create a strong right-angle attachment in sheet-metal applications. Cut-outs often made in panels to form right angles can reduce EMI/RFI shielding. In addition, bent tabs at the edges or in the middle of sheets, bent flanges, right-angle brackets, and tack welds can reduce design integrity.

Solution: The PEM(reg) steel R'ANGLE(TM) threaded self-clinching fastener provides a strong right-angle attachment point in both steel and aluminum sheets as thin as 0.040 inch (1 mm). These Type RAS(TM) fasteners are pressed into a rectangular punched hole in the sheet, mounting securely and permanently with the reverse side of the panel remaining flush. Once the fastener is mounted, the threads on the fastener enable a second panel to be attached to the first using a standard machine screw. The result is an extremely close-tolerance, tight fit that resists vibration and has excellent strip-out characteristics, says maker Penn Engineering.

Steel R'ANGLE fasteners are an alternative to bent tabs at the edge or in the middle of sheets, bent flanges, right-angle brackets, tack welds, and loose hardware. Zinc-plated for corrosion resistance, they can eliminate welding, eliminate tab cutouts for better EMI/RFI shielding, and decrease both the amount of loose hardware and the number of assembly steps. The screws can be removed and reinstalled repeatedly without compromising the fastener's holding power.

Applications: Steel R'ANGLE fasteners can be used for component assembly in the electronic, automotive, aerospace, and telecommunications industries.

Large-head stud delivers speed and security

Problem: Noise shields are often required to meet sound reduction standards. Unfortunately, secure panel attachment can mean more hardware and special panel preparation, increasing assembly time and costs.

Solution: Large Head Rapier Studs enable noise attenuation panels to be securely attached with a lightweight, low-cost fixing, yet be easily and quickly removed. The enlarged head diameter provides a simple and secure quarter-turn fixing method that eliminates the need for supports, washers, or any intermediate elements. Slip-on Long Reach receptacles complement the studs, giving support in ranges from 0.9 to 5.7 mm with maximum torque values of 22.15 in-lbs and 31 in-lbs across three variants.

Applications: Quarter-turn Large Head Rapier Studs are suited for automotive applications, as well as for use in aerospace/aviation, transportation, engineering, office and computer equipment, and white goods assembly.

Handle offers easy installation

Problem: In applications where access to the rear side of a door or panel is limited, a handle that mounts from the rear can be difficult or even impossible to install. The process can involve removing the gasket from the rear side of the door, installing the handle, then re-installing the gasket. Potential results: frustration, extra work for manufacturers, and damage to the customer's product.

Solution: A new grab handle gives users the option of either front or rear installation. Mounting the handle from the front requires no gasket removal, making installation quick and easy, and saving on both time and installation costs, says manufacturer Southco. The mounting hardware is completely concealed by a snap-on cover, which can be stylized with custom colors or company name and logo. The non-corrosive handle is made of tough, high-impact ABS and has a maximum working load of 775N.

Applications: The grab handle is suited for use in many types of cabinets, including gasketed refrigerator cabinets, as well as in furniture, medical equipment, power boxes, and enclosures.

Rivets hasten fastening,save money

Problem: When large quantities of the same type of fastener need to be installed in quick succession, time and installation costs can skyrocket.

Solution: Patented SCHWINGMETALL(reg) rivet mounts are attached by riveting tongs and a customary blind rivet, which is much faster than screwing, says manufacturer ContiTech. The rivet mounts comprise metal parts completely surrounded by natural rubber, which eliminates potential corrosion problems. The mounts can withstand pressure and shear force, and provide the same anti-vibration characteristics available with SCHWINGMETALL mounts with a threaded screw. They damp harmful shocks, insulate machine vibrations, reduce accelerations, and protect against unwanted noise.

Applications: SCHWINGMETALL rivet mounts can be used in the automotive industry and in road construction, where they hold noise protection walls in place. In equipment manufacturing, the rivet mounts can be used to fasten sheet-metal parts, linings, and control cabinets.

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