Modeling a SMT Line to Improve Throughput

Modeling a SMT Line to Improve Throughput
With tools to model a large quantity of products and the impact of SMT line configurations, an electronics assembly plant can be analyzed to identify improvement opportunities.
Analysis Lab


Authored By:

Gregory Vance
Rockwell Automation, Inc.
Mayfield Heights, OH, USA

Todd Vick
Universal Instruments Corporation
Conklin, NY, USA


One of the major challenges for an electronics assembly manufacturing engineer is determining how an SMT machine will impact throughput. Typically an SMT equipment supplier will ask for a few (5-10) products to simulate the throughput capability of their machine. Unfortunately, if the engineer works in a high-mix low volume environment, he may need to know the impact of a new machine on 1,000 or more products. Currently there are no simulation tools to effectively model this. This is confirmed in the 2015 IPC International Technology Roadmap for Electronics Interconnections, which states "In order to better deal with the demands for increased interconnection density and respond to market demands for better return on capital investment in assembly equipment, there is a need within the manufacturing industry for continued improvement in tools and software for modeling and simulation. Needs in this area include better methods of load balancing and improved machine utilization? The tools for determining the balance on assembly lines will need to be flexible to handle the mix of assembly types that manufacturers now face."

Rockwell Automation partnered with Universal Instruments to develop a tool to model a large quantity of products and the impact of varying SMT line configurations. The information used for the modeling includes placements per panel and components placed per hour. With these tools, an electronics assembly plant can be analyzed to identify improvement opportunities and perform "what if" analysis to model impact of machine changes.


The machine and line models can be used to quickly evaluate the throughput and CPH utilization for an entire line in order to select the best machine. With additional tabulations, estimates can reflect the return on investment of replacing a machine. When replacing two SMT machines on an existing line, the Line Model estimated product run time would be reduced by 44 hours per month (32% reduction).

Using (CPHC x VC) and the Product Cycle Time Ratio (PCTR), an engineer can evaluate an entire Plant by line to identify products with greatest improvement opportunity. When used to evaluate a SMT line, eight products with a large Product Cycle Time Ratio (PCTR) where identified and optimized, saving 136 hours of product run time per month (30% reduction).

By evaluating the (CPHC x VC) and brainstorming alternative line configurations, an engineer can perform "what if" analysis to ensure a product is being built on the best line configuration to maximize capacity utilization and throughput.

Products "placements per panel" and "forecasted panel volume" are important factors to consider when choosing what capacity SMT machine to purchase. With information equipment manufacturers have today, they can calculate the CPH equations for their equipment to share with customers to supplement the "IPC-9850" and "Manufacturer Maximum CPH" figures. Together the supplier and customer can understand the impact of different machines for all their products on an SMT line.

Initially Published in the SMTA Proceedings


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