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Custom seals are machined on demand

Aug. 6, 2013
Made-to-order seals are invaluable when prototyping new designs or a critical component fails. Here’s how one company uses proprietary machine tools and software to quickly produce mechanical and fluid seals.

Customized machined seals can be invaluable for engineers and maintenance technicians. Getting a made-to-order seal in a day or two can keep a project on track when prototyping new designs. And custom seals can minimize downtime and lost production when a critical component fails.

But engineers can’t rely on just any machine shop with a lathe to craft quality seals. For one, seals are precision components that demand tight dimensional tolerances to work properly. Making them requires an expertise in machining elastomers and plastics which, on a machine tool, behave quite differently from metals. And most fabricators don’t stock the proper material. In a seal, the right materials are critical for fluid compatibility, shear strength, abrasion resistance, and a host of other reasons.

SKF’s seal machining centers can quickly cut standard and custom seals from a wide range of stock materials.

SKF USA Inc., Lansdale, Pa., can quickly cut seals from stock materials to exact customer specifications. The company can reportedly manufacture seals and related components up to 157 in. in diameter. And larger seals are possible using a welding technique that allows on-site fitting and still provides the performance of a continuous machined or molded seal.

The company catalogs several hundred standard profiles, but can produce virtually any kind of rotating, reciprocating, or static seal for most any conceivable application, says Bryan Uncapher, SKF Business Development Manager for North America.

“We’re able to make a complete range of seals, including rotary seals for grease and oil, V-rings for exclusion, static O-rings, and alternative designs with better performance,” explains Uncapher. Other types include hydraulic seals such as wipers, rod and piston seals, guide rings, and replacements for gland packings, as well as buffer seals and antiextrusion rings, he says.

Seals are made from a wide variety of stock materials, including rubber elastomers, polyurethanes, thermoplastics, and specialty materials like SKF’s ECOPUR, a thermoplastic polyurethane (TPU) with unusually high abrasive resistance, low compression set, and excellent strength. Also available are materials complying with a broad range of industry standards and regulations, such as FDA guidelines. Proprietary materials can also be formulated for specific applications.

CNC-controlled Seal Jet machines produce custom seals using proprietary software and cutting tools specifically developed for machining polymers.

A key to custom capabilities and rapid turnaround, according to company officials, is SKF’s Seal Jet machine. This CNC-controlled production system uses proprietary software and special cutting tools developed for machining different polymers, especially polyurethanes.

All machined seals, whether standard or custom, are manufactured on demand with no tooling costs. Production quantities range from a single piece to lots of several thousand. Larger quantities can be produced using molding processes. Normal lead time is 4 to 5 days, but rush orders for seals up to 24-in. OD can be shipped the same or next day, depending on the time the order is received, says Uncapher.

A range of customers take advantage of customized machined seals from SKF, he notes. These include:

  • OEMs and end users that face performance issues with standard seals, and need to upgrade the materials or design.
  • Users with equipment that suffers a critical breakdown when standard seals are not readily available because they are made overseas, or the machine is outdated and spare parts are no longer sold.
  • Equipment-repair specialists who, instead of replacing worn shafts or damaged housings, opt to change the seal dimensions to fit.
  • OEMs and end users looking to boost machine output through higher speeds and pressures, but need engineering and testing assistance to develop new seal designs that ensure durability and safety.

In the latter case, SKF engineers will work with customers to develop seals tailored to an application’s specific needs. “We have proprietary design and manufacturing software, which helps engineers develop a seal based on the application housing and shaft designs,” says Uncapher.

SKF operates more than 200 seal machining centers worldwide, including in Cleveland and Houston, Edmonton and Scarborough in Canada, and Monterrey, Mexico. Click here to find a location.

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