Multi-seal Rubber Vacuum Cup for CNC Workholding
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Solution Overview
Problem
Existing vacuum cups made from phenolic material are prone to damage and costly, leading to frequent replacements and vacuum seal failures, which can cause machines to idle when new parts are not available.
Innovation Solution
A three-piece vacuum cup made from solid rubber with a flexible lip seal and a cord seal system that allows for redundant sealing, enabling continued functionality even if the lip seal is damaged, and includes features like recessed channels and plugs for partial top use and improved material adhesion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If vacuum cups are made from phenolic material to provide structural strength, then the cups are hard and strong, but the narrow edges are easily damaged and require expensive gaskets for sealing
Solution Approach 1:
The vacuum cup combines rubber material for the sealing surface with phenolic or other structural material for the body. This composite construction allows the rubber lip to provide reliable sealing against damage while the structural material maintains overall cup strength and rigidity.
Solution Approach 2:
Different portions of the vacuum cup are made from different materials optimized for their specific functions: the sealing lip uses rubber for flexibility and seal integrity, while the main body uses phenolic material for structural strength. This local differentiation resolves the contradiction between overall strength and local seal reliability.
2Strength
If phenolic material is used for the vacuum cup body, then the material is hard and resistant to cutting, but the narrow edges crack or break when cutters contact them
Solution Approach 1:
The sealing lip is made from rubber material that is positioned at the narrow edge where cutter contact occurs. This rubber material absorbs cutter impacts without cracking, protecting the phenolic body from damage while maintaining the body's overall resistance to cutter penetration.
Solution Approach 2:
The rubber sealing lip acts as an intermediary between the cutter and the phenolic cup body. It absorbs the harmful mechanical impacts from cutters, preventing direct contact with and damage to the brittle phenolic material while still allowing the body to maintain structural resistance.
3Reliability
If gaskets are added to phenolic cups to form vacuum seals, then sealing capability is improved, but the gaskets are expensive and easily damaged
Solution Approach 1:
The sealing function is extracted from a separate gasket component and integrated directly into the cup structure itself through the rubber sealing lip. This eliminates the need for additional gasket parts, reducing complexity and cost while maintaining reliable vacuum sealing capability.
Solution Approach 2:
The sealing function is merged with the cup body structure by forming the rubber sealing lip as an integral part of the cup. This combination eliminates separate gasket components, simplifying the overall device while ensuring reliable vacuum seals through the flexible rubber material.
4Reliability
If rubber vacuum cups are used to improve durability and sealing, then the cups resist damage better, but they are not suitable for all CNC machine configurations
Solution Approach 1:
The vacuum cup design incorporates universal mounting features and standardized dimensions that allow it to be adapted to various CNC machine configurations. The rubber material itself provides versatility by accommodating different sealing surfaces while maintaining durability across multiple machine types.
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
The rubber vacuum cup is more durable and cost-effective, reducing downtime and maintenance costs by allowing for easy replacement of damaged parts and maintaining vacuum integrity, while accommodating various CNC machine configurations.
Implementation Method 1
A flexible lip seal surrounds the top edge of the top to seal against irregular surfaces
Implementation Method 2
inserting a cord seal into slots in the top to form a second seal
Implementation Method 3
a vacuum passage passes between the bottom surface and the vacuum area
Data Source
AI summary
A three piece vacuum cup is made from rubber to resist damage and facilitates reconfiguring when badly damaged or for specific applications. The vacuum cup includes top, center, and bottom parts. The top is easily and inexpensively replaceable. A flexible lip seal surrounds the top edge of the top to seal against irregular surfaces and damage to the lip seal may be addressed by inserting a cord seal into slots in the top to form a second seal. Part of the top may be cut away to use with small parts and sealed using the cord seal. The center includes a family of passages which may be selectively blocked to permit use of partial tops. A bar pattern on the top has bars aligned in perpendicular directions to better hold material in all cutting directions.