Casing Inner Machining With Counterweight Balance for Large Nozzles

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Large casings with protruding nozzles experience imbalance during high-speed turning processing due to centrifugal forces, leading to reduced processing accuracy and increased processing time.

Innovation Solution

A manufacturing method where a casing forming member with a tubular casing body and protruding nozzles is prepared, then placed on a rotatable table with a tool rotating at a higher speed than the table, allowing for cutting of the inner surface while the table and tool rotate, thereby reducing centrifugal forces and maintaining balance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the table is rotated at high speed for turning processing, then the processing time is reduced, but the centrifugal force acting on the eccentric workpiece increases and processing accuracy deteriorates

Engineering Contradiction:
Improveprocessing timeVSAvoidprocessing accuracy
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies the counterweight principle by adding balance weights to the table to compensate for the eccentric mass distribution of the workpiece. The balance weights are positioned to create counterbalancing centrifugal forces that offset the imbalance caused by the heavy nozzles, allowing high-speed rotation without compromising processing accuracy

Inventive Principle:
Principle #8Anti-weight (Counterweight)

Solution Approach 2:

The patent changes the physical parameters of the rotating system by adding mass (balance weights) to modify the centrifugal force distribution. This parameter change allows the system to maintain dynamic balance at high rotation speeds, resolving the contradiction between speed and precision

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the rotation speed of the table is suppressed to ensure balance, then the centrifugal force influence is reduced, but the processing time is increased

Engineering Contradiction:
Improveprocessing accuracyVSAvoidprocessing time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

By introducing balance weights as counterbalancing elements, the system can rotate at high speeds without experiencing harmful centrifugal forces. The counterweights dynamically compensate for the eccentric mass distribution, enabling both high speed and high precision simultaneously

Inventive Principle:
Principle #8Anti-weight (Counterweight)

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 allows for accurate and efficient processing of large casings by suppressing centrifugal forces and maintaining balance, thus reducing processing time while ensuring high accuracy.

Implementation Method 1

a large centrifugal force acts on the workpiece in an eccentric state due to the suction nozzle or the ejecting nozzle which is a heavy object

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3970891A1Method for manufacturing a casing
Publication Date: 2022.03.23 MITSUBISHI HEAVY INDUSTIES COMPRESSOR CORP
  • EP3970891A1 patent drawingFigure 1
  • EP3970891A1 patent drawingFigure 2
  • EP3970891A1 patent drawingFigure 3

AI summary

A manufacturing method of a casing includes a step of preparing a casing forming member that includes a casing body forming portion which is formed in a tubular shape and a protruding portion forming portion which protrudes from the casing body forming portion toward an outer side in a radial direction, a step of placing the casing forming member on a table which is rotatable about a table axis which extends in a vertical direction and disposing a tool which is rotatable about a tool axis on an inner side of the casing forming member in the radial direction, and a step of forming the casing by performing cutting an inner circumferential surface of the casing forming member with the tool while rotating the table about the table axis together with the casing forming member and rotating the tool about the tool axis.