Scroll Machining Using Stationary Cutter and Rotating Workpiece

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Solution Overview

Problem

Conventional scroll machining methods, such as milling, suffer from low precision, long machining periods, and high costs due to the need for specialized cutters that meet specific hardness requirements, resulting in inefficient and costly processes.

Innovation Solution

A scroll machining method where the scroll is rotated around its center axis while a non-rotary cutter machines the side wall surfaces, with interchangeable blades, and additional cutters handle end and peripheral surfaces, all while the scroll is clamped and fixed, improving precision and efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If milling is adopted to machine the scroll, then the scroll wall can be machined, but the machining precision is low and the machining period is long

Engineering Contradiction:

Improvemachining precisionVSAvoidmachining efficiency

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

Instead of rotating the milling cutter to machine the scroll wall, the invention inverts the approach by rotating the scroll itself while using a stationary cutter. This inversion allows the workpiece to move rather than the tool, enabling precise control of the cutting path and improving both machining precision and efficiency

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The invention replaces the traditional rotating milling cutter mechanism with a stationary cutter and scroll rotation mechanism. This substitution changes the mechanical system from tool rotation to workpiece rotation, achieving better machining results

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Reliability

If a milling cutter meeting specific hardness requirement is used, then the scroll wall can be machined, but the cutter needs frequent replacement increasing machining cost

Engineering Contradiction:

Improvecutter durabilityVSAvoidmachining cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

By inverting the machining approach from rotating cutter to rotating scroll with stationary cutter, the invention eliminates the need for high-hardness rotating cutters, thereby reducing cutter replacement frequency and machining costs

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The stationary cutter used in the invention can be simpler and less expensive than the high-hardness rotating milling cutters required by traditional methods, reducing overall machining costs

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Productivity

If the scroll is machined with stationary scroll and rotating milling cutter, then machining can be performed, but the machining period is long

Engineering Contradiction:

Improvemachining speedVSAvoidmachining period

Core Design Contradiction:

ProductivityVSLoss of time

Solution Approach 1:

The invention inverts the traditional machining approach by making the scroll rotate while keeping the cutter stationary, which enables continuous machining of the scroll wall surface and significantly reduces the machining period

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

By rotating the scroll during machining, the invention enables continuous cutting action along the scroll wall surface, eliminating the need for repeated positioning and setup operations, thus reducing total machining time

Inventive Principle:

Principle #20Continuity of useful action

Data Source

PatentUS10328544B2Scroll machining method and scroll machining apparatus

Publication Date: 2019.06.25 DANFOSS (TIANJIN) CO LTD

AI summary

In a scroll machining method, a scroll has a disc-like end plate and a scroll wall extending from a first side surface of the disc-like end plate, and the scroll is driven to rotate around a center axis C of the scroll, and a first cutter machines a side wall surface of the scroll wall while the scroll is rotating. The first cutter is a non-rotary cutter. When the scroll is machined, the scroll rotates around its center axis, and the first cutter does not rotate around its axis, thereby improving the scroll's machining precision and machining efficiency.