Frequently Asked Questions

What's the difference between an oil seal and a hydraulic seal?

An oil seal is a rotary seal that prevents lubricant leakage and contamination on a rotating shaft, while a hydraulic seal is a linear-motion seal that contains pressure in a cylinder's reciprocating parts (piston/rod). POLY STAR supplies both in NBR, FKM, urethane and other materials matched to your operating conditions. Oil Seal & Bearing Isolator · Hydraulic & Pneumatic Seal

Can you make custom, non-standard sized seals?

Yes. POLY STAR's Machined Seal line produces non-standard dimensions and special shapes not in standard catalogs, machined to drawing. Call +82-2-2637-6200 to discuss.

Which material should I choose for high-temperature or high-pressure conditions?

For high temperature, FKM (Viton), PEEK or PTFE-family materials are recommended; for high-pressure reciprocating motion, spring energized seals work well. Share your operating temperature, pressure and media and POLY STAR will propose the optimal material.

NBR vs. FKM (Viton) oil seals — how do I choose?

NBR is economical for mineral-oil, room-temperature service (roughly -30 to 100°C); FKM (Viton) suits synthetic oils, high temperatures (roughly -20 to 200°C) and chemical resistance. Tell us your media and temperature range and we'll recommend a material.

Urethane (PU) vs. rubber (NBR) seals — which is better?

Urethane resists wear and high pressure (e.g. excavators); NBR offers general-purpose hydraulic performance at lower cost. Choose PU for high-pressure, high-wear duty and NBR for general sealing. Share your conditions for a recommendation.

What causes hydraulic seal leakage?

Common causes include seal wear/hardening, scored or scratched rods, incorrect material selection, overheating/over-pressure, and assembly errors. Re-selecting the right material and profile often resolves it. Send a damaged sample and POLY STAR can diagnose the cause and remanufacture the seal.

How is a bearing isolator different from a regular oil seal?

A bearing isolator seals with a non-contact labyrinth design, protecting bearings virtually wear-free over the long term — an advantage over contact-type oil seals in high-speed, low-friction applications. See Bearing Isolator

How do I check O-ring specifications (KS/AS568)?

O-rings are sized by inner diameter (ID) x cross section (CS), following Korean KS or U.S. AS568 (inch) standards. Measure your existing O-ring or send a drawing and POLY STAR will match the spec and material.

What cleanliness and chemical-resistance requirements apply to semiconductor equipment seals?

Semiconductor process seals need to hold high vacuum, resist plasma and process gases, and generate very low particles. POLY STAR addresses this with PTFE, PEEK and spring energized seals; specific cleanliness grades depend on your process, so please consult with us.

What extreme conditions (cryogenic/vacuum) suit spring energized seals?

A metal spring embedded in the PTFE sealing lip maintains contact force across temperature swings, making these seals suitable for cryogenic, high-vacuum, high-temperature and low-friction environments such as semiconductor and aerospace equipment. POLY STAR offers six spring types. See Spring Energized Seal

What environments suit PEEK and PTFE (Teflon) seals?

PTFE offers low friction, chemical resistance and a wide temperature range; PEEK offers higher strength, pressure resistance and temperature capability. Both suit chemical, semiconductor and high-load environments. POLY STAR also machines PEEK back-up rings and components to order.

How is an ACM bearing different from a regular bearing?

Here, "ACM bearing" refers to a low-friction sliding bearing (bushing/guide), not a rolling bearing — used to reduce friction and wear in linear and oscillating motion parts of industrial machinery and semiconductor equipment. See ACM Bearings

How does a magnetic filter remove iron particles?

As hydraulic oil or cutting fluid passes through the filter, a strong magnet attracts and captures iron and metal wear particles, reducing equipment wear and failure and extending service life. POLY STAR supplies the OEI and BPS lineups sized to your line. See Magnetic Filter

Can you make seal kits for excavator hydraulic cylinders?

Yes. POLY STAR manufactures and supplies piston seals, rod seals, dust seals and back-up rings as kits for boom, arm and bucket cylinders, in urethane, PTFE and more. Send your model/dimensions or an existing seal sample for matching (+82-2-2637-6200).

Do you supply oil seals for marine propeller shafts?

Yes, oil seals for marine applications are available, made from materials suited to shaft diameter and operating conditions (seawater, lubrication). Exact applicability depends on your specifications — please contact us with drawings and conditions.

Can you reproduce a seal from a drawing or a damaged sample alone?

Yes. Even without a drawing, POLY STAR can reverse-engineer the dimensions and shape of a damaged sample and machine an identical replacement. Send a sample or measurements for a quote.

Is there a minimum order quantity (MOQ)?

Low-volume, high-mix custom machining is available, so small orders are welcome. The exact MOQ depends on the product, material and machining complexity — contact +82-2-2637-6200 or info@sealstar.com.

What are your lead times?

Lead times differ between stocked standard items and custom-machined parts, and depend on quantity, material and complexity. Exact lead times are provided with your quote. POLY STAR's own inventory management system supports fast direct supply.

How is the operating temperature and pressure range determined?

A seal's limits are set by material (NBR -30 to 100°C, FKM -20 to 200°C, PTFE + energizer -50 to 250°C, etc.), profile, dimensions and media. Share your operating temperature, pressure and fluid and POLY STAR will select a suitable material and design.

How do I request a quote or technical consultation?

Call +82-2-2637-6200 or email info@sealstar.com. Share your operating conditions (temperature, pressure, media, dimensions) or a drawing/sample and POLY STAR will propose a custom quote and material. Go to Contact