Modeling an SMT Line to Improve Throughput


Reading time ( words)

Rockwell-Table2_May2018.jpgTable 2. Sample range of placements per panel versus count of assemblies and forecasted panel volumes.

The idea of using simple regression to develop a model of “placements per panel” to CPH began to develop. This relationship was first studied using production history.

Machine Mathematical Model for CPH

A report was available that contained panels built and total time to build a work order. This report was used to calculate the average CPH per panel for an SMT machine model. A scatter plot with a smoother line was used to view the relationship between the variables for a machine model. The smoother line is a line fitted to the data to explore the potential relationships between two variables, without fitting a specific model, such as a regression line.

There is a relationship between “placements per panel” and CPH but there are points that do not follow the smoother curve. The other observation is that actual CPH values vary greatly compared to the specification value the manufacturer stated.

Since production data was used to model this relationship, all the problem areas outlined earlier represent part of the performance and added noise in the model. Another idea was to use generic product simulation data from the manufacturer. The product simulation information included:

1. Quantity of placements per panel

2. Simulated cycle time for a SMT machine

3. CPH (calculated)

This would filter out the noise from production and machine configuration issues and could then be used to establish a realistic CPH equation. With the simulated cycle time data, the relationship between “placements per panel” and CPH was then studied.

The scatter plot revealed a relationship between “placements per panel” and CPH. Using the Pearson Correlation Coefficient, the strength of the relationship is assessed. At 0.536 it is considered moderate and P-Value of 0.000 means the relationship is statistically significant. This indicates that “placements per panel” is a good predictor of CPH.

To read the full version of this article, which appeared in the May 2018 issue of SMT007 Magazine, click here.

Share

Print


Suggested Items

Bill Cardoso Discusses Creative Electron’s Inspection Strategy

04/03/2019 | Tim Haag and Barry Matties, I-Connect007
At PCB West in Santa Clara, California, Dr. Bill Cardoso of Creative Electron held a class on advanced packaging and X-ray inspection strategy. Guest Editor Tim Haag and Publisher Barry Matties met with Bill to further discuss his class and the importance of turning inspection data into information.

Investigation on the Assembly Process for m03015 and a Brief Look at m0201 Components

11/14/2018 | David Geiger, Robert Pennings, and Jane Feng, Flex
Components continue to shrink in the SMT world, and the next evolution of passive components includes m03015 (009005) and m0201 (008004). The m03015 and the m0201 components will see primary adoption in products that require further miniaturization, which would be SiPs. These modules would then be assembled into products through attachment, another assembly, or via other interconnect methods. This article explores the development of an assembly process (SMT only) for the m03015 component.

Flex Circuit Assembly: Challenges and Strategies for Success

07/27/2018 | Stephen Las Marias, I-Connect007
The flexible printed circuit market is on track for growth. But dealing with flex circuits during assembly is very different from rigid PCBs. This article highlights some of the assembly challenges when working with flex circuits, and strategies to address them.



Copyright © 2019 I-Connect007. All rights reserved.