Automated Saw System for Crooked Lumber Precision Cutting

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Solution Overview

Problem

Automated cutting systems for lumber fail to accurately cut crooked lumber pieces, leading to deviations in length and reduced precision, especially when making mitered cuts, due to the inability to compensate for warpage and crookedness, resulting in substandard truss assembly and potential damage to heavy lumber members.

Innovation Solution

An automated saw system with a conveyor and adjustable saw that detects deviations from straight lumber using sensors, allowing for precise adjustments in the saw's position and angle to ensure accurate cutting through the lumber's width, accommodating crookedness and maintaining correct lengths and mitered ends.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If automated cutting systems make no allowance for warpage or crookedness of lumber members, then the cutting process is simple and fast, but the length of the board after the mitered cut deviates significantly from the specified length

Engineering Contradiction:
Improvecutting precisionVSAvoidsystem complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system performs preliminary measurement of lumber crookedness using sensors before the cutting operation. This advance detection allows the control system to calculate and apply appropriate compensation values to the cutting parameters, ensuring precision cuts are made despite the lumber's natural imperfections.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses sensors to detect the actual position and crookedness of the lumber member, feeds this information back to the control system, which then adjusts the cutting parameters accordingly. This closed-loop feedback mechanism ensures that cuts are precise even when lumber dimensions vary from specifications.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If crooked lumber pieces are forced to a straight orientation using hydraulic or pneumatic pistons, then the cutting precision is improved, but the lumber member springs back to its pre-straightened status after the force is released

Engineering Contradiction:
Improvecutting precisionVSAvoidcut stability
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The system replaces the mechanical straightening mechanism (hydraulic or pneumatic pistons) with a measurement and calculation-based approach. Sensors detect the lumber's actual position and crookedness, and the control system calculates the appropriate compensation, eliminating the need for physical straightening forces that cause springback.

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

Solution Approach 2:

Instead of physically changing the lumber's orientation through mechanical force, the system changes the cutting parameters (saw blade position, angle, and path) to accommodate the lumber's actual crooked state. This parameter adjustment allows precise cutting without disturbing the lumber's natural position.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If heavier lumber members such as 2x12 members are forced to a straight orientation, then the cutting precision may be improved, but the force required may exceed the equipment capacity or the lumber may split, crack or break

Engineering Contradiction:
Improvecutting precisionVSAvoidlumber damage
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The system eliminates the need for high-force mechanical straightening equipment by using non-contact sensors to detect lumber position and a control system to calculate compensation. This substitution avoids the risk of damaging heavy lumber members with excessive straightening forces.

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

Solution Approach 2:

The control system acts as an intermediary between the sensor detection and the cutting operation. It processes the sensor data, calculates the appropriate compensation parameters, and adjusts the cutting mechanism accordingly, eliminating the need for direct mechanical intervention on the lumber itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of manufacture

If mitered cuts are made on crooked lumber without compensation, then the cutting operation is simple, but the finished length is significantly altered due to the crookedness

Engineering Contradiction:
Improvecutting operation simplicityVSAvoidfinished length accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The system performs preliminary measurement of the lumber's crookedness using sensors before the mitered cut is made. This advance detection allows the control system to calculate the appropriate compensation and adjust the cutting parameters, ensuring the finished length is accurate despite the lumber's natural imperfections.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses sensors to detect the actual position and crookedness of the lumber member, feeds this information back to the control system, which then adjusts the cutting parameters accordingly. This closed-loop feedback mechanism ensures that mitered cuts produce accurate finished lengths even when lumber dimensions vary from specifications.

Inventive Principle:
Principle #23Feedback

Data Source

PatentEP1896228B1Automated system for precision cutting crooked lumber
Publication Date: 2012.12.26 MITEK HOLDING INC
  • EP1896228B1 patent drawingFigure 1
  • EP1896228B1 patent drawingFigure 2
  • EP1896228B1 patent drawingFigure 3

AI summary

An automated saw system for cutting a crooked piece of lumber with a mitered end and a length. The saw system includes a saw for cutting the piece of lumber, a lumber feed conveyor for feeding the piece of lumber to the saw, and a sensor that measures a deviation amount by which the piece of lumber deviates from an idealized straight piece of lumber. A controller communicates with the sensor to adjust either the saw or the conveyor in response to the detected deviation amount so that the piece of lumber is cut to correspond to a cut of the idealized straight piece of lumber.