Vision systems check up on direct part marking

Siemens uses vision systems all along its fuel pump production line to read and inspect directly marked codes at each point of production.

Siemens cannot afford any uncertainty when it comes to production for its high profile automobile clients.

Safety and quality control has become of the utmost importance in this industry.

This means that complete traceability of each individual part is essential.

For the production of fuel pumps at the Asnieres (France) production plant, Siemens chose Technifor to ensure this traceability using direct part marking (DPM) on the body of each gasoline pump.

Siemens is using Cognex In-Sight vision systems all along the production line to read and inspect directly marked codes at each point of production.

Siemens VDO is a leading international automotive supplier of electronics and mechatronics.

As a development partner within the automobile industry, the company manufactures a comprehensive range of products relating to engine management electronics and fuel injection.

For the production of two different kinds of gasoline pumps, Siemens needs to ensure each one is marked with two different codes.

The position of the codes must be verified and the codes need to be read correctly so that each piece is recorded as having been appropriately marked and checked in a database as it passes each check point on the production line.

There are two assembly lines.

One assembly line uses an alloy material for the body and the second assembly line uses stainless steel.

Each body needs to be marked using two codes; one alphanumeric and the other Datamatrix so that each piece is identifiable by means of a unique code.

Once the codes are marked the pieces undergo a series of checks and controls on the production line.

At each stage the code needs to be verified and read.

First, the codes are verified to ensure their positioning is accurate.

Secondly, the code is read in order to check that it is legible: this is vital.

The code needs to be correctly positioned on the body of the part in question, a part which may be defective or difficult to manipulate.

Plus, this same part needs to be correctly read and identified in order to avoid any disruption to the production line.

Clients demand a standard of "zero nonread" which means no piece can get through as not having been read.

Even one "nonread" piece would necessitate a manual intervention which would not only compromise the "white room" environment but would also slow down the production flow.

Technifor was entrusted with the mission of marking and reading the codes during the production of each gasoline pump.

They decided to use the direct part marking process of "dot peening".

This is a direct impact marking process used to mark codes onto hard or metal surfaces.

The pump surfaces are either stainless steel or aluminium, and so these different surface textures increased the challenge.

Added to this is the environmental aspect in that production would have to be carried out under "white room" conditions.

The reading and verification of codes in these circumstances requires a robust and high performing solution.

A final need of the client demanded that each production check be recorded so that at each control point an accurate trace is kept on each pump in question.

These details are automatically entered into a database which is integrated into the client's operations.

For example the point of inspection which ensures the pump is water-tight.

Here the code is verified by the camera, read by the camera and the fact that it has been inspected at this precise point is recorded and the result is fed into the database.

The nature of the technical constraints and the challenging circumstances of the application meant that machine vision was the only solution.

Cognex In-Sight cameras proved the only reliable means for code verification and reading as well as being capable of co-operating with the data collection process.

In-Sight vision systems are high performing even in difficult environments.

The constraints of this application required robust vision systems and the marking process involved is extremely effective and chosen for its durability.

The nature of marking by peening requires a high performing vision solution capable of reading 100% of the codes while coping with low contrast and surface reflection difficulties.

Siemens is able to respond to the demands of their clients thanks to the capabilities of Cognex vision systems.

Each part leaving Siemens is traceable from "cradle to grave" ensured by Technifor "mark and read" relying on Cognex vision systems.

Siemens can now assure their clients that the entire process of production is controlled, inspected and recorded from start to finish.

They can also prove that each piece is completely traceable and has been correctly inspected.

By taking advantage of the best of advanced technology Siemens is ensuring they maintain a competitive edge and pass the benefits onto their clients.

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