PCB Allocation via Integer Linear Programming

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Solution Overview

Problem

The existing methods for allocating printed circuit boards to assembly lines are often done manually or semi-automatically, leading to unbalanced allocations that result in high utilization of one assembly line and low utilization of another, causing inefficiencies and suboptimal use of the assembly system.

Innovation Solution

A method using integer linear programming to allocate circuit boards to assembly lines, optimizing the distribution of component variances across lines to minimize setup changes and reduce the number of setup families, thereby improving the uniform distribution of component variances and reducing the frequency of assembly line conversions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual or semi-automatic allocation methods are used, then the allocation process is simple to implement, but the utilization of assembly lines becomes unbalanced with high variance in component variances

Engineering Contradiction:
Improveallocation process simplicityVSAvoidassembly line utilization efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent replaces manual or semi-automatic allocation methods with an automated integer linear programming system. The control device automatically detects requirements and allocates circuit boards to assembly lines using mathematical optimization, eliminating human intervention in the allocation process and achieving balanced utilization of all assembly lines.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the allocation parameters by using integer linear programming to optimize the assignment of circuit boards to assembly lines. The system considers multiple parameters simultaneously (component variances, production times, capacity constraints) and finds the optimal allocation that minimizes the variance of component variances across assembly lines, thereby balancing the utilization.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If assembly lines are allocated without optimization, then the allocation process is fast and simple, but the number of setup changes and setup families increases

Engineering Contradiction:
Improveallocation speedVSAvoidsetup change frequency
Core Design Contradiction:
ProductivityVSLoss of time

Solution Approach 1:

The patent performs preliminary optimization of the allocation before production begins. The control device detects all requirements and calculates the optimal allocation using integer linear programming in advance, taking into account future setup changes and armor families. This preliminary action minimizes the number of setup changes required during production by strategically grouping circuit boards that require the same components together.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent creates a virtual model of the allocation problem using integer linear programming equations that represent the real-world constraints and objectives. The control device solves this mathematical model to find the optimal allocation, which is then implemented in the physical production system. This copying approach allows for rapid optimization without directly manipulating physical resources.

Inventive Principle:
Principle #26Copying

3Device complexity

If unbalanced allocation is made, then the allocation process requires less computational effort, but the assembly system cannot be used optimally with high variance in component variances

Engineering Contradiction:
Improveallocation computation complexityVSAvoidassembly system efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent creates a universal allocation system that can handle multiple objectives simultaneously using integer linear programming. The control device optimizes for balanced component variances, minimized setup changes, and efficient utilization of all assembly lines at the same time. The system is designed to work with any number of assembly lines and circuit board types, making it universally applicable to different production scenarios.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent replaces simple heuristic allocation methods with a sophisticated integer linear programming system. The control device uses mathematical optimization algorithms to automatically balance component variances across assembly lines, ensuring optimal utilization of the entire assembly system rather than relying on simple rules that cannot account for multiple constraints simultaneously.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Adaptability or versatility

If frequent setup changes are performed, then the assembly lines can adapt to different circuit board requirements, but the operation cost increases and production efficiency decreases

Engineering Contradiction:
Improveassembly line adaptabilityVSAvoidproduction efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The patent performs preliminary optimization to minimize setup changes before production begins. The control device uses integer linear programming to group circuit boards into allocation groups that share common component requirements, thereby reducing the frequency of setup changes during production. This preliminary planning maintains adaptability to different circuit board requirements while minimizing the number of times setup changes are needed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent aims to maintain continuous production by minimizing interruptions for setup changes. The optimal allocation groups circuit boards in a way that allows assembly lines to process multiple boards without changing the armor or setup, thereby maintaining continuous useful action and improving production efficiency while still adapting to different requirements through strategic grouping.

Inventive Principle:
Principle #20Continuity of useful action

Data Source

PatentEP2842402B1Allocation of printed circuit boards on fitting lines
Publication Date: 2018.09.05 SIEMENS AG
  • EP2842402B1 patent drawingFigure 1
  • EP2842402B1 patent drawingFigure 2
  • EP2842402B1 patent drawingFigure 3

AI summary

The invention concerns a fitting system comprising a plurality of fitting lines for fitting printed circuit boards with electronic components. A method for allocating printed circuit boards to the fitting lines comprises the following steps: determining of requirements for fitting each of a plurality of printed circuit boards with components to be fitted thereto; and allocating of the printed circuit boards to fitting lines under predetermined conditions by means of integral linear programming, the allocation being carried out such that the component variances of the fitting lines are as similar as possible, the component variance of a fitting line representing the number of different components which are to be fitted to all printed circuit boards allocated to the fitting line.