Multipole Rod Assembly Fabrication Using Precision Spacers
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Solution Overview
Problem
Existing methods for fabricating multipole rod assemblies, such as those used in mass spectrometers, face challenges in achieving high precision and symmetry while being cost-effective, with previous approaches requiring precise machining and potentially damaging or misaligning the rods during assembly.
Innovation Solution
The solution involves using a fixture with precision-made spacers and adhesive bonding of conductive rods to isolation rings via shoes, which allows for precise alignment and assembly without the need for high-precision machining of the isolation rings, and uses materials with matched thermal expansion coefficients to maintain inner radius invariance with temperature changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional methods are used to attach rods to isolation rings, then assembly is possible, but manufacturing precision and symmetry are compromised
Solution Approach 1:
The patent introduces shoes as intermediary components between the rods and isolation rings. These shoes serve as mediators that simplify the attachment process while maintaining precise rod spacing. The shoes are adhesively attached to both the rods and isolation rings, creating a buffered connection that accommodates manufacturing tolerances and reduces the complexity of direct high-precision attachment.
2Manufacturing precision
If mandrels are used for alignment during assembly, then rod positioning accuracy is achieved, but mandrel removal becomes difficult and may damage rods
Solution Approach 1:
The patent extracts the alignment function from a permanent mandrel structure and implements it through temporary spacers that are easily removable. The spacers are positioned between the rods during assembly to maintain precise spacing and symmetry, then can be cleanly removed after the adhesive bonds are established, avoiding the removal difficulties and potential rod damage associated with traditional mandrels.
3Manufacturing precision
If high-precision machining is performed on isolation rings, then rod assembly symmetry is improved, but manufacturing costs and complexity increase
Solution Approach 1:
The patent segments the precision requirements across multiple components: the shoes and spacers are manufactured with high precision to ensure correct rod spacing and positioning, while the isolation rings themselves can be manufactured with lower precision. This segmentation of precision requirements allows the critical dimensional control to be concentrated in the smaller, more easily precision-manufactured shoes and spacers, rather than requiring the entire isolation ring assembly to be high-precision machined.
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 simplifies the fabrication of multipole rod assemblies, ensuring high accuracy and symmetry while reducing thermal stress and material distortion, and allows for easier and faster assembly with reduced costs by spreading the precision requirements across reusable spacers.
Implementation Method 1
a plurality of shoes, each shoe adhesively attached, such as by means of epoxy resin, on one of its edges to a corresponding rod
Implementation Method 2
uses materials with matched thermal expansion coefficients to maintain inner radius invariance with temperature changes
Data Source
AI summary
A multipole rod assembly, such as used as mass analyzer, is fabricated using rods adhesively attached to shoes, which are then attached to isolation rings. A fixture is used in conjunction with precision-made spacers to precisely assemble the ion mass analyzer. The rods and shoes can be made of metal, while the isolation rings are preferably made of insulator, such as ceramic. The shoes and isolation rings need not be made to high precision, as the spacer ensures high accuracy in alignment and symmetry of the rods. Consequently, the rods are the only precision machined parts in the ion mass analyzer assembly.