HTF Featured Product: SI® Threaded Inserts

    Penn Engineering’s Durable, High Quality Inserts for Plastics In Stock and Ready to Ship

    Choosing the best threaded insert for plastic applications can be challenging and is critical to the integrity of your product assembly. A global leader in the manufacturing of threaded inserts for plastics and other fasteners, Penn Engineering offers strong, high quality SI® Inserts for a wide range of plastic assemblies and insertion methods.

    Hi-Tech Fasteners Inc. (HTF) is proud to be a manufacturing partner with Penn Engineering. As a Penn Engineering partner, we always carry a deep and diverse array of Penn’s SI® Inserts—including press-in, molded-in, and ultrasonic (heat-staking) inserts—that can be shipped the next day.

    Let’s take a quick look at the different types of Penn Engineering SI® Inserts available in HTF’s inventory that are available for next day shipping services.

    SI® Brand Threaded Inserts for Plastics

    SI® brand inserts employ press-in, molded-in, or heat/ultrasonic installation methods to provide strong, reusable, permanent threads in plastic. Regardless of your insertion method, HTF has the plastic insert you need.

    SI® Brand Ultrasonic/Heat-Staking Insert Featured Products

    Tapered, Thru Threaded (Types IUA, IUB, IUC)

    Tapered, thru threaded inserts, types IUA (aluminum inserts), IUB (brass inserts) and IUC (stainless steel inserts) are designed for use in tapered holes. A tapered mounting hole allows for rapid and accurate alignment prior to installation.

    Straight Wall Thru Threaded (Types IUTA, IUTB, IUTC)

    Straight wall, thru threaded inserts, types IUTA (aluminum inserts), IUTB (brass inserts) and IUTC (stainless steel inserts) are designed for use in straight holes. Self-aligning lead-in of inserts provides for accurate alignment prior to installation.

    Symmetrical, Thru Threaded (Types ISA, ISB, ISC)

    Symmetrical, thru threaded inserts, types ISA (aluminum inserts), ISB (brass inserts) and ISC (stainless steel inserts) are designed for use in straight or tapered holes. Symmetrical design eliminates the need for orientation.

    Heat-Staking Threaded Inserts Process Overview (Thermoplastics Only)

    This approach is for thermoplastic use only, offering high performance along with lower overall costs. This process involves the insert getting heated with a thermal press until the insert melts a small part of the hole’s edges while it is being pushed into the thermoplastic assembly. Melted resin then seeps and fills the knurl pattern to form a firm bond once hardened. This is the most typical thermoplastic insertion process because it's less costly and is amenable to automation processes, allowing multiple insertions at a time. 

    Ultrasonic Assisted Threaded Inserts Process Overview (Thermoplastics Only)

    Ultrasonics are also deployed to melt the periphery of the hole. While heat-staking uses heat to melt the hole edge, the ultrasonic method uses a vibration frequency to achieve melting. Unlike heat-staking that is easy to control, ultrasonic insertion has greater control requirements, as the application of the vibrations needs to be very precise to avoid material damage. The ultrasonic process is less easily automated and is less frequently utilized. 

    SI® Brand Molded-In Insert Featured Products

    Blind Threaded (Types IBA, IBB, IBC)

    Blind threaded inserts, types IBA (aluminum inserts), IBB (brass inserts) and IBC (stainless steel inserts) have a blind end, which protects the threads from plastic intrusion.

    Self-Locking, Blind Threaded (Type IBLC)

    Self-locking, blind threaded, type IBLC (stainless steel inserts) has deformed threads which lock the screw in place to resist vibration. The blind end protects the threads from plastic intrusion.

    Thru Threaded (Types ITA, ITB, ITC)

    Thru threaded inserts, types ITA (aluminum inserts), ITB (brass inserts) and ITC (stainless steel inserts) include a pilot diameter and undercuts allowing the plastic to flow into grooves, providing high pullout resistance.

    Thru Threaded, Knurled Spacers (Types STKA, STKB, STKC)

    Thru threaded, knurled spacers, types STKA (aluminum inserts), STKB (brass inserts) and STKC (stainless steel inserts) include a uniform knurl diameter which reduces the risk of sink marks. Available in varying lengths for injection molding assemblies.

    Molded-In Threaded Inserts Process Overview (Thermosets and Thermoplastic Application)

    This method ensures the very best pullout and torque performance. This process involves machine-directed insertions into the mold; resin is then added to completely encase the insert, which creates a super strong bond. However, a more complicated core with close tolerances between the pins and inserts is required for the molded-in approach. The process also tends to take more time than heat-staking and ultrasonic processes. 

    SI® Brand Cold Pressed-In Insert Featured Products

    Hexagonal (Types NFPA, NFPC)

    Hexagonal inserts, types NFPA (aluminum inserts) and NFPC (stainless steel inserts) provide strong, reusable threads with no heat or ultrasonics required. The hexagonal "barbed" configuration ensures high torque-out and pullout values.

    Thru Threaded (Type PPA, PPB)

    Thru threaded, types PPA (aluminum inserts) and PPB (brass inserts) are press-fit inserts with strong, reusable threads. No heat or ultrasonics are required. The slotted insert compresses allowing easy access into the mounting hole.

    Flange-Head (Type PFLA, PFLB)

    Flange-head, types PFLA (aluminum inserts) and PFLB (brass inserts) are press-fit inserts with strong, reusable threads. No heat or ultrasonics are required. The flange-head eliminates direct contact of plastic with mating parts. The slotted insert compresses allowing access into the mounting hole.

    Straight Knurl (Type PKA, PKB)

    Straight knurl, PKA (aluminum inserts) and PKB (brass inserts) are press-fit inserts with strong, reusable threads. No heat or ultrasonics are required. The straight knurling at the top end of the insert offers higher torsional resistance. The slotted insert compresses allowing access into the mounting hole.

    Cold Pressed-In Threaded Insert Process Overview (Thermosets)

    This is the easiest and least costly plastic insertion method that requires a basic press for execution. Essentially, inserts are simply pressed into the thermoset plastic mold; this approach results in a weaker bond and overall strength, but generally is a sturdy alternative that will work and save on costs. Although they may not perform as well as the aforementioned types, cold pressed-in inserts are a highly economical alternative because they are easy to install and typically do not require special auxiliary equipment.

    HTF has a track record of more than 30 years of delivering the components our clients need when they need them. We have been a trusted distributor partner to countless companies and we are always poised to help you in any way we can. 

    Order your SI® Brand threaded inserts for plastics by 3pm EST and we’ll get them out to you the same day. We’re poised and ready to help.

    We take great pride in having what you need and getting it to you when you need it, while delivering the highest level of customer service in the industry. That’s why the top manufacturers in the industry partner with us.

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    “We at Penn Engineering recognize and appreciate Hi-Tech’s investment in expanding into Canada.”

    John O’Brien PEM Director of Sales-Americas

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