Punching Method for Bodywork Parts with Variable Speed

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Solution Overview

Problem

The existing process for mounting parking assistance sensors and headlamp washers on motor vehicle bodywork parts is inefficient, requiring two separate operations after painting, which can lead to scratching and increased costs due to the use of slow and powerful actuators, and results in a larger punching station footprint.

Innovation Solution

A punching method where the punch is moved at a high speed for the approach stroke and a low speed for the piercing stroke, using a combination of standard cylinders and a force reduction mechanism to separate the approach and punching steps, allowing for faster cycle times and reduced risk of scratching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a powerful cylinder providing a punching force of 1000 daN is used to achieve quality punching without threads or burrs, then manufacturing precision is improved, but productivity deteriorates due to the slow movement speed of 1 mm/s

Engineering Contradiction:
Improvepunching qualityVSAvoidcycle time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The punching operation is divided into two distinct phases: an approach phase where the punch moves at high speed (50 mm/s) to cover the distance from the support to the workpiece, and a punching phase where the punch moves at low speed (1 mm/s) to ensure quality cutting. This segmentation allows the system to achieve both high productivity during approach and high precision during the actual punching operation.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If powerful cylinders moving at slow speed are used to ensure punching quality, then manufacturing precision is improved, but device complexity increases due to the need for expensive adjustable jacks

Engineering Contradiction:
Improvepunching qualityVSAvoidactuator system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The system employs a dynamic approach where the punch movement speed is varied according to the operational phase. During the approach phase, the punch moves at high speed (50 mm/s) using standard cylinders, and during the punching phase, it transitions to low speed (1 mm/s). This dynamic speed variation eliminates the need for expensive adjustable jacks while maintaining punching quality.

Inventive Principle:
Principle #15Dynamics

3Area of stationary object

If the punch is positioned close to the part to reduce footprint, then area of stationary object is reduced, but reliability deteriorates due to the increased risk of scratching the painted surface during transfer

Engineering Contradiction:
Improvepunching station footprintVSAvoidsurface protection
Core Design Contradiction:
Area of stationary objectVSReliability

Solution Approach 1:

The high-speed approach phase allows the punch to quickly cover the distance from the support to the workpiece, minimizing the time the part is handled and reducing the risk of scratching the painted surface. By completing the approach phase rapidly, the system protects the surface while maintaining a compact station footprint.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method reduces the risk of scratching and minimizes the footprint of the punching station while maintaining quality, enabling faster and more cost-effective production by using standard cylinders and reducing the need for expensive adjustable jacks.

Implementation Method 1

separate the steps of approaching the punch and of punching proper (designated here "drilling") by use of the punch. Thus, in the event that an approach stroke of 300 millimeters would be provided to leave space around the part in order to avoid scratching it, the displacement of the punch from its rest position to its use would take 2 to 3 seconds, without the quality of the punching being degraded, since the actual punching (i.e. "drilling") is always carried out at a reduced speed no more than 10 millimeters per second.

Methodology Applied
Scientific EffectForce reduction mechanism: Mechanical Advantage

Data Source

PatentEP2576161B1Method and machine for punching bodywork components
Publication Date: 2015.10.14 COMPAGNIE PLASTIC OMNIUM SA
  • EP2576161B1 patent drawingFigure 1~2
  • EP2576161B1 patent drawingFigure 3~4
  • EP2576161B1 patent drawingFigure 5~6

AI summary

The invention relates to a method for punching bodywork components, notably outer skin components, so that parking aid sensors or headlamp washers can be fitted therein. The invention also relates to a punching machine comprising a bearing element (2) on which a bodywork component is placed, a punch (19) and movement means (5, 10) for moving the punch firstly over a first course to bring it into a position of use, and then over a second course to pierce said component. The punch moves over the second course at a speed that does not exceed 10 mm/s and is slower than the speed of the movement of the punch over the first course. The movement means for moving the punch over the second course comprises a punching ram (11, 21) coupled to a power reduction mechanism. The invention finally relates to use of the machine and to a bodywork component obtained by implementing the method.