Injected Metal Assembly Solution Profiles

Zinc Alloy Instant-Cure Bonding

Molten zinc alloy is a powerful bonding agent which can be a highly effective alternative to many instant-cure adhesives. It exhibits properties common to adhesives, such as excellent stress distribution and the ability to join a diverse range of dissimilar materials and those of different thicknesses. The zinc alloy bond, however, requires no special surface preparation, has no peeling and thermal degradation issues common with conventional adhesives, and performs well in harsh environments. The molten alloy bonds materials in milliseconds as it "cures", with the bonded components immediately ready for use. Read our article about zinc bonding or download it as a PDF (336K).

Control cables

Cast terminations help to significantly reduce costs. They provide great flexibility as virtually any shape can be cast onto the cable in a single operation. Strength and accuracy meets and often exceeds our customer's requirements The IMA process helps to eliminate assembly of pre-manufactured and/or purchased termination fittings.

Cast terminations are used in a variety of applications by automotive, aircraft, power garden tools and other industries.




«  This tooling resembles tooling used
     for cable applications



Household appliances - Manufacturing cost is slashed in producing a high specification threaded bushing.

Production costs are cut by almost 50% by casting a zinc alloy threaded bushing onto a stamped steel cover plate. Most of the savings in manufacturing this appliance switch subassembly result by eliminating a machined aluminum bushing previously staked to the cover.

Quality is improved with part-to-part consistency over very long runs.

  • bushing concentric to datum diameter within 0.05 mm (.002") TIR.
  • M10x .75 thread is cast to a 6g specification (high precision bore diameter held to 0.1 mm (.004") TIR.
  • high strength as alloy shrinks and locks onto the base plate.

Internal combustion engines - only the IMA process could maintain the close tolerances critical to component performance.

A sintered hub and seven brass pistons are assembled by die casting a carrier plate, locking the components in position. Glass-filled plastic injection molding and press fitting were rejected because of high cost and/or lack of durability.

Tight tolerances are critical for this piston carrier which is used in a solenoid actuated oil pump for two stroke engines.

  • true position of the pistons are held perpendicular to the guide shaft OD to within 0.1 mm (.004")
  • piston end faces are held perpendicular to the guide shaft OD within 0.05 mm (.002").


Hardware - manufacturing cost is cut by 38% and rejects/ field failures are eliminated.

A hex shank is die cast directly onto a drill bit for a 38% reduction in manufacturing costs and circular runout is held to 0.5 mm (.020").

Cost reduction results from the elimination of a fabricated, predrilled steel shank which was swaged to the drill bit, plus improvement in quality and productivity.

  • the strong mechanical lock withstands high torsional load
  • no rejects or field failures
  • tooling inserts reduce costs by producing six different size drill bit assemblies using the same basic tool.

Electrical controls - the IMA process eliminates quality problems and improves productivity.

Air gaps resulted when crimping a heat sink to a bimetal strip used in industrial thermostats. To eliminate this problem, the heat sink is die cast directly onto the bimetal strip, becoming an integral part of the assembly with full surface contact.

As well as improved integrity and part-to-part production consistency:

  • the pre-manufactured heat sink is replaced with a less expensive zinc alloy casting
  • production increased to over 400 assemblies an hour
  • inserts for the basic tool reduce costs for production of two different sized assemblies.


Electronics - single manufacturing process replaces multi-step assembly and ensures tight tolerances.

Two separate production processes (swaging and soldering) are replaced by the less expensive method of injecting a zinc alloy hub to join a silver-plated brass pin to a zinc alloy seizure block used in cable TV signal amplifiers.

Cost savings result from reducing two operations to one. The process maintains the required electrical conductivity and forms a strong joint.

  • end of the pin is held within ±0.13 mm (±.005") relative to the block surface
  • true position of the pin's outside diameter is held within 0.36 mm (.014") relative to its datum surfaces.

Automotive - the IMA process replaces expensive manufacturing alternatives and allows high speed production.

Production costs are slashed by die casting a zinc alloy stepped shaft to capture a steel collar and an oil impregnated sintered bronze bearing. Other options, such as press fitting the components to a shaft or machining the shaft from a bearing material, were too
expensive.

After determining that the IMA process was most costeffective, the assembly was designed to take advantage of the process.

  • high speed production - 600 assemblies an hour
  • dimensional tolerances of ±0.13 mm (±.005")
  • total runout of the bearing OD relative to the collar OD is 0.10 mm (.004") TIR.

Automotive - Higher capacity die casting system improves production and cuts assembly costs.

With FisherTech's Injected Metal Assembly process, zinc alloy rings are cast directly onto the ends of rods in a completely automated assembly process, replacing a time-consuming and costly welding operation.

For more information, read about the ZF Lemforder stabilizer link (231K PDF).

Office Equipment - the IMA process gives design freedom and forms a strong mechanical bond between components.

Virtually any shape of zinc alloy configuration can be cast to join components. This design freedom allows a functional block of alloy to lock a sintered bronze bushing to a stainless steel rod for a printhead pivot block used in a computer printer.

Dimensional and positional tolerances are critical as well as strength.

  • dimensional tolerances are typically ±0.13 mm (±.005")
  • alloy block is stronger than the components it joins
  • virtually and shape can be formed to meet functional requirements.

Solution Profile: Liquid Rivets

Molten alloy cost-effectively replaces conventional riveting with a "liquid rivet" which "shrink locks" components with a strong mechanical bond. Productivity and quality problems caused by differences in hole location, hole size tolerance and alignment between the components are easily solved as the "liquid rivet" completely fills the rivet holes. It can compensate for misalignment up to ¼ of the hole diameter. Production rates vary from 300 to 1000 per hour depending on the complexity and number of components being liquid riveted. A fixturing tool accurately positions the components from the outside features for the liquid riveting operation. The alloy (usually zinc) in injected, and within a few milliseconds, the riveted assembly is ejected - ready for use.

  • Liquid rivets have high tensile and shear strengths
  • Liquid rivets provide a strong mechanical bond - severe vibrations will not loosen the "shrink lock"
  • Liquid rivets are automatically watertight and airtight
  • Even extremely brittle or fragile materials can be riveted as no force is applied during the operation
  • The high speed of the liquid riveting operation leaves heat-sensitive materials undamaged
  • Virtually all materials can be liquid riveted
  • The fixturing tool can often accommodate liquid rivets of different length or diameter for reduced costs
  • One step production - If riveting is only one step in an assembly process, molten alloy joining techniques may be able to replace other operations such as swaging, brazing, press fitting. All joining operations can take place at one time in the fixturing tool. It is not uncommon to reduce as many as five joining steps to one with a liquid rivet

Application Profile: Anvil Sub-Assembly

Who would ever have thought that you could eliminate a complex riveting operation with a simple one-shot "liquid" rivet? Molten zinc alloy becomes a liquid rivet using the IMA process. An anvil sub-assembly used to crimp terminations onto electrical wiring required two rivets to join a 3.81 mm (0.15") thick steel bar to an 8.89 mm (0.35") thick steel bar. It is much faster and more economical to use the molten alloy to flow into the holes and instantly lock the two bars together.

Previous production method:

  • Two riveting operations.

IMA process:

  • The bars are held together as the alloy "shrink locks" them.

IMA system used:

  • Semi-automatic system.

Benefits:

  • cost reduced and higher production rate
  • two riveting operations eliminated
  • high precision
  • tooling holds the bars accurately for liquid riveting
  • part-to-part consistency.