Fasteners—screws, washers, rivets, specialty clips, nuts and bolts—join parts together, while other mechanical devices, such as springs, store and release energy, maintain alignment and manage loads by changing shape under force. Advances in material science now bolster the integration and precision of these components. Surging demand in sectors like aerospace, automotive and medical devices guarantee their relevance.
The following are a handful of examples of how these components meet the increasingly stringent demands of modern manufacturing.
1. A Nested Wave Spring in a Crest-to-Crest Configuration
What would a design engineer do when tasked with packing the power of a traditional coil spring into just half the space? They would probably turn to a wave spring solution.
The most important design advantage of a wave spring is that it can provide the same force and deflection as a traditional coil spring, but in a reduced axial space that often requires about 50% less axial height, according to Smalley, the manufacturer and inventor of the edgewound wave spring and Spirolox retaining rings.
This Fall, Smalley will launch a nested wave spring in a crest-to-crest configuration. Nestawave springs are coiled from a single, continuous piece of wire. According to the spec sheet, these springs combine the deflection characteristics of a crest-to-crest wave spring with the force output of a Spirawave nested spring. The resulting design offers high force and significant travel in a compact design. Smalley noted that the new spring will be available as a custom solution. Custom parts make up more than 70% of Smalley’s business.
Wave springs are ubiquitous across industries. In aerospace, wave springs optimize space and performance efficiency in landing gear systems. In automotive, find them in drivetrain parts, clutch assemblies and suspension systems. Manufacturers of machinery and equipment order wave springs for die applications, power tools and industrial automation systems. Wave springs are also commonly specified in lifesaving medical devices and robotic surgical instruments.
2. Improving Fastener Compatibility with ANSI Inch Countersunk Holes
Misumi's on-demand manufacturing platform, meviy, has expanded its sheet metal and off-the-shelf fastener capabilities. Engineers can now design and submit parts for ANSI-standard inch countersink holes ranging from #0 to 7/8 in., with a standard 82-deg. countersink angle. The feature is intended for parts made from steel, stainless steel and aluminum. The feature supports better part mating and potential cost savings through greater hardware availability.
3. Cam Lever Lineup Expedites Actuation Clamping
Fixtureworks is building up its workholding range with the addition of new cam levers, the QLCL, QLCCS and the QLCA. These cam levers have an ergonomic design and are ideal for fast cycle time operations requiring quick loading, securing and unloading. They can handle clamping forces up to 1,200 lb, depending on size. Compared to conventional cam handles, QLCL levers have a higher resistance against vibration and feature a noticeable click feel at clamping end.
They are constructed from cast aluminum, stainless steel, steel with black oxide finish or plastic. A setscrew and internal pad are included to help prevent the levers from backing off and loosening during operation. In addition to cam levers, Fixtureworks’ range of workholding and fixturing components includes shaft coupling clamps, ball lock fasteners, pneumatic clamps, sliding locks, spring plunger clamps, positioning elements and linear actuators.
4. Specification Update Following Design Refinement of Plastic Screws
NBK (a.k.a. Nabeya Bi-tech Kaisha) has been operating in the American markets since 2015 under the subsidiary NBK America LLC. The company’s provenance can be traced to 1560 in Japan, where it first developed cast-iron products. NBK’s footprint today extends to an eclectic range of products that are used in manufacturing equipment for semiconductors, robotics, machine tools and medical devices.
Count among their high-quality miniature shaft couplings specialty screws such as vacuum application screws, and wireless positioning units (although these are not for the U.S. market). Most recently, NBK issued a specification update to its plastic screws (PEEK/Hexgon Bolt), model SPE-M4-H. A slot on the head will be removed, but there will be no change in the main material or physical properties such as temperature tolerance, tightening torque and chemical resistance.
NBK explained the reason for the change in an email to Machine Design: “The reason for the screw shape change to the M4 in the SPE-H is that the other sizes were already designed as non-slotted. To maintain consistency across the product line, we have standardized all sizes to the non-slot type.”
5. Lubrication-Free Leadscrew Assemblies
Leadscrews are much more than mere threaded rods. Specifically, leadscrews are mechanical linear actuators that convert rotational motion into linear motion. They consist of a threaded shaft (the screw) and a nut that travels along the thread. As the nut moves along the thread, it creates a controlled motion or force. Typical uses are in linear actuators, CNC machinery, 3D printers, medical devices, industrial automation equipment, and aerospace and defense systems.
Leadscrew assemblies from Igus are engineered for maintenance-free operation. They’re made from self-lubricating composite plastic materials. This removes the need for external lubricants and coatings. One example is the dryspin high-helix series. These high-helix leadscrews have multi-start options, are not self-locking (they may need an ancillary brake or clamp) and feature a proprietary asymmetrical thread profile tailored to the plastic leadscrew nuts. Their specialized geometry supports higher speeds and, according to Igus, delivers up to 30% longer service life compared to conventional thread profiles. Igus produces these in aluminum and stainless steel and offer six leadscrew nut material options.
