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Process Engineering and achieving optimum manufacturing flow a dream? (Part 3)

Jay Gorajia

Jay Gorajia

Posted Jan 18, 2011

 Let’s say we are chasing the dream to achieving optimum manufacturing flow? 

This is the 3rd post in a series of how to achieve optimum manufacturing flow in an assembly factory.

There are many opportunities for improvement in factories, and only those willing to investigate, identify, plan and act to make changes, will succeed. Can you lose business because a factory has lead-times and delivery times longer than their competition, due to an less-than optimized factory? Absolutely!

Bottleneck management in Process Engineering

Process engineering has a huge impact on the manufacturing flow, and the effectiveness of the shop-floor producing products in an optimum way.  Process engineering is where a lot of the data originates in the factory.  Manufacturing engineers assess how products will be build, and create the appropriate documentation and recipes to drive the manufacturing equipment and processes on the shop floor. 

When recipes or programs are sent to the production floor, especially into SMT, there are various optimizations that can be done to ensure optimum manufacturing flow. Reducing any usage of production equipment for non-value added activities to production of products, such as program validation or shape-data validation, it would dramatically improve the manufacturing flow. 

SMT Machines use sophisticated cameras and sensors to ensure that the component that is placed matches the shape-data defined in the SMT Machine library, as a way to ensure the right part is placed.  However, the cameras have very tight tolerances, and components outside those tolerances may be rejected by the SMT machine.   Increased rejected parts add to the cost, since those parts would have been purchased, in a specific quantity.  When a Bill of Materials calls for multiple component vendors for a specific part number, to ensure that all of them are ‘within tolerance’ a quick AVL Check should be done.  This ensures that machine downtime is avoided due to parts out of tolerance by the component distributor or vendor.

  Valor AVL Check

The Bill of Materials (BOMs) are created ensuring component Function, and rely on the vendor documentation to ensure Form and Fit.  There are variances in Vendor Part Numbers that are subtle and can lead to incorrectly defined parts.  As a worse case, parts can be ordered that are the correct Function, but are very far from the defined pad stack defined in the Design data.

Using accurate part library modeling technology, overlaying parts from a defined BOM over pad stacks is the only way to ensure correct Fit and Form of components before placing it on the SMT Machine and spending expensive and valuable production time for this validation. 

This activity would eliminate the product-hold that occurs when alternate parts are called in the middle of a production run, which may not be the same form factor (by height, pin length, pin width or body dimension).

Another frequent cause of production delays and lead times is shape-data and orientation validation.  Shape Data must be created to ensure the machine ‘recognizes’ the component, and know which parameters to use when picking and placing that specific component.  Validation of shape-data requires software to have SMT Machine shape-data library managed within the software, where that shape-data can be visually overlaid onto the Design data pad stacks. 

  MSS Virtual Sticky Tape

Mentor’s MSS product, vPlan, has a Virtual Sticky Tape module that will enable an engineer to validate rotations and orientations offline, based on the shape data defined for a specific SMT Machine and ensure the parts (especially polarized parts) are placed in the correct rotations.

Identifying areas of non-value added time and resources is essential in getting a leaner more optimized manufacturing flow.  The production holds and delays described above can add hours or even days to a work order production, lengthened the delivery time.  Lengthened delivery times translate to a delay in revenue recognition!

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Jay GorajiaJay Gorajia is Worldwide Consulting Manager, PCB DFM and Manufacturing Solutions, for the Consulting Division of Mentor Graphics. He works to improve efficiency and help define productivity solutions in design, manufacturing engineering and production for OEMs and PCB Assembly manufacturers. Mr. Gorajia holds a Bachelor’s degree (B.Sc.) in Electronic Engineering and a Masters in Business Administration (MBA) in Technology Management. He has published a number of articles and White Papers in industry leading technical magazines and industry conferences. Visit Electronics Assembly .… Exposed

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