Induction Heat Staking & Reflow

How does induction heat staking work?

Sometimes called thermal staking (or plastic reflow, indirect heating) is a process by which a metallic insert is heated and pressed into a plastic material which has been drilled with a hole that is slightly smaller than the insert, resulting in an interference fit as the plastic melts and reflows around the insert.

Induction generates an electromagnetic field in a work coil that induces currents in the conductive material of a workpiece placed within or near the coil. Friction from these currents elevates the temperature of the workpieces to be inserted.

Benefits of Using Induction for Heat Staking

Induction heating delivers precise, consistent heating results to meet tight production tolerances. Our non-contact induction staking solutions provide targeted, localized heating without open flame.

Since induction heats only the metal inserts, the process is efficient and repeatable.

heat staking Application Notes

Select from our collection of heat staking notes, taken from years supporting our customers. Read how we helped to solve their process heating challenges.

image: Heat Staking Steel Parts Heat Staking Steel Parts

To heat steel inserts to be placed into a plastic frame. The end product is an automotive part.

image: Metal-to-Plastic Insertion with a Brass Shaft Metal-to-Plastic Insertion with a Brass Shaft

Multiple torches were required for this application previously, so the compact EASYHEAT minimized the required footprint for heating. With induction you can expect the same result every time, while variability is often observed with a torch

image: Metal-to-Plastic Insertion with a Steel Insert Metal-to-Plastic Insertion with a Steel Insert

The power was turned on for five seconds and the part was monitored during heating and for 15 seconds after.

image: Heating a Steel Pin for Fan Insertion Heating a Steel Pin for Fan Insertion

An EASYHEAT and its workhead require a minimal footprint, saving the client valuable floor space compared to heating alternatives

image: Heating Steel Inserts for Metal-to-Plastic Insertion Heating Steel Inserts for Metal-to-Plastic Insertion

It took 5 seconds with a 2 kW EASYHEAT to reach temperature, which melted the plastic for a solid bond without cracking the molded plastic.

image: Heating four brass inserts prior to insertion into a plastic motor housing Heating four brass inserts prior to insertion into a plastic motor housing

Using induction heating, the parts came to the required temperature in just 15 seconds in a highly repeatable heating method and a coil plate could offer protection against operator movement/errors

image: Heating stainless steel inserts for an insertion application Heating stainless steel inserts for an insertion application

Induction offers dramatically faster heating when compared to ultrasonics; faster heating means there is the potential to dramatically increase production rates with a highly repeatable and easy-to integrate processes.

image: Heating brass inserts for metal-to-plastic insertion Heating brass inserts for metal-to-plastic insertion

Innovation: Ambrell's Applications Lab was able to solve a problem that a competitor couldn't solve, which is a key benefit when purchasing induction solutions from Ambrell

image: Bonding plastic handles onto metal brooms Bonding plastic handles onto metal brooms

With a more reliable induction heating system, they will not have to worry about lost production due to power supply issues that come with an unreliable system

image: Metal-to-plastic insertion of threaded magnetic steel inserts Metal-to-plastic insertion of threaded magnetic steel inserts

Outdated equipment and poor responsiveness drove this customer to a new vendor who could help them with new or improved processes for new or enhanced solutions

image: Induction Bonding an Arthroscopic Device Induction Bonding an Arthroscopic Device

Induction is used to bond the device sheath to collet. Innovative coil design lifts production rate.

image: Heat a steel shaft for metal-to-plastic insertion Heat a steel shaft for metal-to-plastic insertion

Induction heating provides hands-free heating that involves no operator skill for manufacturing, even distribution of heating and localized application of energy limits temperature drift

image: Inserting brass bushing into plastic wire connector Inserting brass bushing into plastic wire connector

A three turn helical coil is used to heat the brass bushing. The brass bushing is heated for 2 seconds and then placed on the wire connector & pressed into position.

image: Heating magnetic steel for insertion into polypropylene for pallet manufacturing Heating magnetic steel for insertion into polypropylene for pallet manufacturing

Induction heating provides 'greener' manufacturing of pallets using reusable, recyclable materials, hands-free heating that involves minimal operator skill for manufacturing and even distribution of heating

image: Inserting threaded brass parts into plastic thermostat housing Inserting threaded brass parts into plastic thermostat housing

This application has three different coils for varying hole patterns. A three turn oblong coil is used to heat 2 brass inserts in close proximity.

image: Inserting a piston stop with o-ring into an oil pump assembly Inserting a piston stop with o-ring into an oil pump assembly

Induction heating provides increased production speed, simpler tooling for customer, hands-free heating that involves no operator skill for manufacturing

image: Bonding of electric motor shaft to nylon face fan Bonding of electric motor shaft to nylon face fan

Induction heating provides hands-free heating that involves no operator skill for manufacturing, only the metal shaft is heated so the motor is not affected, increased production due to rapid heating, decreased failure rate, originally used glue which ran into motor and caused failure and stronger bond

image: Heating Four Inserts Simultaneously Heating Four Inserts Simultaneously

The brass inserts are to be heated prior to insertion into a plastic automotive sub assembly

image: Brass Inserts Brass Inserts

Heating is to be accomplished within 5 seconds, and can be done in a helical coil since pick and place manufacturing is employed.

image: Plastic Lawn Chairs Plastic Lawn Chairs

To heat internally threaded steel inserts to a temperature above 650F for insertion into plastic lawn chair assemblies.

image: Brassiere Underwire Brassiere Underwire

To heat the ends of 0.072-inch spring wire, spaced 1/2 inch apart, uniformly for the application of nylon powder on a 1inch length of the end.

image: Inserting Steel Studs into a Plastic Tail Light Inserting Steel Studs into a Plastic Tail Light

To heat threaded steel studs for insertion into a plastic tail-light assembly at 450°F.

Thermoplastics will flow at elevated temperatures and the solidified polymer can be re-heated to re-flow around the insert. Thermosetting polymers, once the shape has been cast, will no longer melt or flow on reheating. Table 1 shows some typical temperatures, time and power required for different materials, as established in the Ambrell Applications Lab.

The diameter of the insert hole must be the correct size to allow the plastic to flow around the insert. If the hole is too small,extra plastic will be displaced. This displaced plastic is commonly called ‘flash.’ Excessive heat and pressure may also cause flash. If the hole is too large, not enough plastic will flow into the fins and knurls to achieve the desired holding strength.

10 Induction Heating Application Notes

We have collected these 10 popular Application Notes to help you understand the many ways induction heating can improve your heating processes.

10 Automotive Application Notes

We have collected these 10 popular Application Notes to help you understand the many ways induction heating can improve your precision automotive manufacturing processes.