Crimping & Crimp Quality - Issue 3
One might be overwhelmed to know the importance of the crimp applicator for crimp quality. Although specific parts must be manufactured individually for nearly every terminal, this only has a limited effect on the average market price.
The crimp applicator is the “heart“ of the crimping process – regardless whether it is carried out semi-automatically or fully automatically. With the deformation of the crimping ears of a crimp terminal, the degree and type of deformation are determined by the crimp applicator and its terminal-specific parts (tooling), such as crimp die and anvil. Only tooling that is optimally matched to the crimp terminal to be processed can assure high crimp quality.
Beat Locher, Product Manager for Schleuniger: “Our crimp applicators stand for quality without compromise at an extremely attractive price.“ He judges the requirements for quality and precision of the tooling as follows: “If the terminal-specific parts are not precisely made, then even the best crimp machine will not be able to achieve a good result. At Schleuniger, we design and manufacture not only crimp applicators, but also crimping machines, StripperCrimpers, fully automatic crimping machines and transfer systems, so we know only too well the importance of the crimp applicator as the central element in production.”
Therefore, from the very beginning, key factors in Schleuniger crimp applicators have been designed with the highest precision and to be maintenance-friendly. As proof of quality for customers, every crimp applicator is tested internally and a ground cross-sectional view is prepared.
Central Role of the Feed
Next to an optimal, terminal-specific design of the tooling, the basic design of the feed plays a central role. With banded terminals, the feed is responsible for the exact positioning of the terminal parts before crimping. At first glance, it appears to be of secondary importance whether the feed is pneumatic or mechanical. Deviations from the ideal position with either types of feed can lead to faulty crimping.
Transport distance = distance between
two crimp terminals on the carrier strip
Mechanical or Pneumatic?
With mechanical feed, the vertical stroke of the crimping press is “translated” into a horizontal transport movement of the terminal carrier strip, so that after each crimp, the next terminal part is brought into the exact pre-defined position between the anvil and crimp die. As the distance between two terminals on the carrier strip is usually different between different terminal types, most applicators have user adjustable settings for setting the terminal feed stroke and terminal position. Pneumatic feed is often used in automatic operation, in order to achieve the highest level of accuracy for positioning and precision over large transport distances. The advantage of pneumatic feed is that the transport movement is not coupled to the press stroke directly. Therefore, the speed and timing of the feed can be controlled individually.
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UNI-A with mechanical side-feed
(side-feed applicator) |
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UNI-A with mechanical rear-feed
(rear-feed applicator) |
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UNI-A with pneumatic side-feed
(side-feed applicator) |
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UNI-A with pneumatic rear-feed
(rear-feed applicator) |
Side- or Rear-Feed?
Depending on how the terminal is positioned on the carrier strip, the feed must either take place from the side (= side-feed applicator) or from behind (= rear feed applicator). Internationally, the universal crimp applicator with a stroke of 40 mm and a shut height of 135.788 mm (height of applicator in closed state) predominates, but as far as feed direction (which is determined ultimately by the terminal manufacturer) is concerned, all types are still to be found in the global market: feed from the side (left or right possible) or feed from rear – naturally, all with different terminal pitches.
Depending on how the terminal is positioned on the carrier strip, the feed must either take place from the side from left or right (=side-feed applicator) or from behind
(=rear-feed applicator)
Numerous Settings
In order to achieve optimal crimping, numerous terminal-specific settings can be made on the crimp applicator: from basic parameters, such as crimp height of the wire and insulation crimps, to fine-adjustments of the bell mouth, terminal end position, compensation of play, and adjusting the force of the terminal braking system. It is a decisive advantage if settings, such as those with the Schleuniger Uni-A, can take place directly in the crimping press so that any necessary adjustments can be made quickly and verified directly.
What is Standard?
At least in Europe, the 40 mm stroke and the 3-point mounting of an applicator in the press are defined as standard. In general, these applicators are appropriate for wire cross-sections up to 6 mm² (AWG 10). For larger cross-sections or for use with flat foil cables, there is as yet no international standard.
As a worldwide company, Schleuniger offers, for example, the Uni-A standard crimp applicator in different designs (mechanical / pneumatic / side-feed / rear-feed), with special designs for closed barrel terminals, 30 mm stroke or as a double crimp applicator. Next to the FlexoCrimper (a special standard applicator for high-speed automatic production), Schleuniger also has special tools for cross-sections up to 50 mm² as well as solutions for crimping of flat foil cables (FFC / FPC) in the product range.
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