The use of a preforming tool for angular sensors allows them to be prepared before they are soldered on an electrical circuit. To collect a signal of the measured angle, the angular sensors are used. The position of an element can thus be detected from these sensors. For example, the level of the fork on a forklift truck.

The different technologies of angular position sensors

It is possible to find four main technologies of angular position sensors:

  • Hall effect: the use of Hall effect sensors allows the measurement of angular displacement.
  • Potentiometer: which consists of a mobile part coupled to the part, whose displacement is measured, and a fixed part, attached to the element that supports the mobile part. The angular displacement is limited by the potentiometer. The amplitude of the latter is then measured according to the variation of its resistance between the mobile cursor and one of the two fixed limits.
  • Optical encoder: the information returned by the optical encoder is always digital. In most cases, it is information coming from an optical device comprising a photodetector, a source of light and a grooved disc. The optical encoder can be rotary or linear, depending on the type of movement to be measured. With a grooved disk, it is possible to measure an angular displacement with the rotary encoder. A linear encoder, on the other hand, allows the measurement of a longitudinal displacement from a graduated and transparent rule.
  • Resolver: which is a kind of small transformer, consisting of two offsets of 90 ° and a primary. The primary is supplied by a sinusoidal voltage. In the secondary, there are two sinusoids shifted by 90 °. The phase shift of these two sinusoids with the primary constitutes the image of the angular position to be measured. The flux induced by the primary to the secondary can vary, depending on the angle between the primary and the two secondary. The angular position information returned by the resolver is in the form of two voltages that vary sinusoidally.

There are several applications of an angular position sensor: motion study, dimensional control and detection of the position of elements

Sensors are Tested before their Application

In the laboratory, the programming and testing of angular position sensors is carried out on a test bench. This is an equipment which, at speeds ranging from 100 to 10,000 Rpm, allows the programming of hall effect sensors. This test bench has a shaft line which is driven by a motor. The latter is controlled by a test PC allowing the targets to be rotated at a maximum speed of 10,000 Rpm.

In order to detect a possible bad assembly or drift of the target, the shaft line is balanced and the level of vibration in operation is monitored. A 36,000 pts/rev incremental encoder delivers the angular position of the shaft to the PC in order to synchronize the angular position of the target with the sensor signals.

The test bench is semi-automatic. Thus, before testing and programming, a seal is applied by the operator to the product using a seal mounting clamp.

First, the automatic tests of non-electrical characteristics (insert, bundle length, presence and color of seal, etc.) are started by the operator by the action of the cycle start push button.

By means of an RLC bridge, the measurements of the capacities and the electrical controls are carried out by a PC. The programming of the cell is done by the PC thanks to the signals obtained from the movement of the target which is driven by the rotary table. Each conforming product will then be put in the case after an engraving by micro-percussion.

Hall Effect Angular Position Sensors

Changes in magnetic fields can be measured with hall effect position sensors. When a conductive element is introduced into an electromagnetic field, a force is created that is proportional to the current and the fields.

When a magnetic field is detected, the hall sensor transmits a signal. This sensor is therefore mainly used as a speed or position sensor.

Currently, hall sensors are more robust and less expensive than optical encoders.

Angular Sensor Preforming Tool

The angular sensors can be prepared, before being soldered on electronic circuits, with a tool allowing their preforming. Two types of machine tools can be found on the market:

  • Manual machine: the operator uses his strength to bend the sensor with a crank. A manual machine can be inexpensive and is more suitable for prototyping machines, which will equip position or speed sensors, and for schools. As an educational tool, the manual machine provides users with a good understanding of how well sensors can be preformed.
  • Automatic machine: has the advantage of high cutting and bending accuracy. Most hall effect angular position sensors can be cut and preformed with this machine. This machine is automatic and modular and can be easily integrated into a production line. The production rate can be increased while reducing the amount of waste. For example, it is possible to preform up to 900 sensors per hour from an MGA Technologies cutting and bending machine.

MGA Technologies Preforming Tool Characteristics

MGA Technologies has developed a modular machine tool. It can be configured as a conveyor belt, a bucket or a shuttle. It is also possible to integrate it into an automated production line and to interconnect it with one or more existing machines.

Technical specifications of the MGA Technologies angular sensor preforming tool

  • Power supply: 110V to 230V,
  • Cambering accuracy: < 2°,
  • Cutting accuracy: +- 0.1 mm,
  • Speed of 900 angular sensors / hour,
  • Preforms magnetic or non-magnetic sensors from 3 to 5 legs,
  • Noise level lower than 70 dB,
  • Multilingual interface for better handling for users around the world.

Integration of the Angular Sensor Preforming Tool in an Assembly Line

The modular angular sensor preforming tool manufactured by MGA Technologies can be integrated into any type of production tool. Indeed, for nearly forty years, this company has specialized in the creation, installation and commissioning of special, custom-made machines for the automotive, precision mechanics, food processing, aeronautics and pharmaceutical industries.

We can mention, for example, the assembly machine for diagnostic cards, the transfer machine for pharmaceutical filters, the automatic line for the manufacture of vaccines, the automatic line for the preparation of kits and many others.

The company’s team provides support throughout the customer’s project, even for the installation of the angular sensor preforming tool.