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A tour around the factory

A view of what is involved in making Parabolic Springs


The production takes several stages and we like to show you around to give you an idea of the production process of our parabolic springs.

The tour starts in the 'raw material' warehouse.

Storage of tons of material ready for production. Because the factory wants to keep this stock low it is clear that this is only a small part of the annual production.

Cutting and Tapering

First the metal will be cut to the correct length and heated to enable tapering at the right temperature.

Furnace to heat the material prior to tapering

This furnace is used to heat the material, one side of each leaf, prior to tapering. A conveyor belt moves the material slowly under the heat source of the furnace to unsure even heating and correct end temperature.

Directly after the leaves come out the furnace they will be tapered, one side each time. This is done by a laminator which will press (while rolling) the tapered thickness, to the parabolic sequence we calculated. It's being extracted from the laminator, center to edge, in two stages.

2 stage tapering sequence

2 stage tapering sequence

Rolling of the eyes

The rolling of the eye will be done after heating the leaf ends in a similar furnace. The end of the leaf will be wrapped around a mandrill which gives the eye the correct diameter, within the specified tolerances.

Heat treatment and quenching

Main furnace to heat the material for final heat threatment

This is the main furnace to heat the material for final heat treatment. Unlike the other furnaces this furnace will heat the complete leaf, however also in a constant and controlled way, to ensure all stresses will be taken out.

Setting and quinshing of the heated material. After cooling down, the spring ability of the material will be effective

After the heating, the leaf will be placed in the setting and quenching machine, by a robot, where it is clamped into the right camber. Then it is moved slowly into the temperature controlled oil to cool down the leaf and to give it it's spring ability. This part of the production is crucial for a top quality spring. Therefore it is controlled by computer according the ISO 9002 standards, on which the whole production is based.

Assembling the spring

After cooling down to room temperature, in several carefully controlled stages, the leaves will be stress shot-peened to prolong the life of the spring. The micro cracks, that could be present, will be closed by shooting small particles at high velocity onto the stress surface of the leaf.

Individual leaves are ready for shot peening

Individual leaves are ready for shot peening

The Final assembly of the spring prior to load testing

The Final assembly of the spring prior to load testing

Load testing

Load test 1 Load test 2

Load testing sequence is operated by a computer. It will measure camber, force and rate while compressing the spring and letting it rebound, in one dynamic movement, on a special rig. All springs that are conform our specifications will pass this test. The springs that are not conform are rejected and disposed off.

Coating

All springs are coated (sprayed) in the well know 'HST Blue' which can be considered a trade mark for top quality parabolic springs.

Although all springs are 'hot stamped' with their part number we still spray this number on the main leaf for indentification

Although all springs are 'hot stamped' with their part number we still spray this number on the main leaf for identification.

Packing for storage and shipment

Packed springs ready for dispatch Final checking by the quality controler Packed springs ready for dispatch Packed springs ready for dispatch

This is only one of the many batches we make and sell during one year. 
Efficient production and handling ensure quick and effective dispatch to our customers all over the world.


1997 - 2006 Heytee Automotive bv