CMM Thermal Control Using Heating Above Ambient

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Solution Overview

Problem

Coordinate measuring machines (CMMs) face challenges in maintaining precise temperature control, especially in varying ambient conditions, leading to reduced measurement precision and requiring expensive, sensitive cooling systems or energy-intensive conditioning environments, which are not suitable for portable or outdoor use.

Innovation Solution

A CMM with an active temperature control system that uses a control unit, temperature sensors, and heating elements to maintain a constant temperature above ambient levels, incorporating passive thermal insulation and air-guiding tunnels for efficient thermal management, allowing for operation in changing environments with high precision.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If cooling systems or air conditioning are used to stabilize temperature, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

Instead of cooling the CMM structure below ambient temperature to compensate for thermal expansion, the invention heats the structure above ambient temperature. This inverted approach achieves thermal compensation without requiring complex cooling systems, refrigerating elements, or liquid coolant circuits, thereby reducing device complexity while maintaining measurement precision.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention extracts and eliminates the need for complex external air conditioning systems and internal cooling mechanisms by using a simplified heating-only approach. The temperature control system achieves thermal stability through heating elements and insulation alone, removing harmful cooling components from the system.

Inventive Principle:
Principle #2Taking out (Extraction)

2Measurement precision

If cooling systems are used for temperature stabilization, then measurement precision is improved, but device weight increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoiddevice weight
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The invention inverts the conventional cooling approach by using heating elements to raise the CMM structure temperature above ambient levels. This eliminates the need for heavy cooling systems, refrigerating elements, and liquid coolant circuits, significantly reducing device weight while maintaining measurement precision.

Inventive Principle:
Principle #13The other way round (Inversion)

3Measurement precision

If air conditioning environments are used, then measurement precision is improved, but energy consumption increases

Engineering Contradiction:
Improvemeasurement precisionVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by stationary object

Solution Approach 1:

Instead of using energy-intensive air conditioning to cool the environment, the invention uses heating elements to actively warm the CMM structure above ambient temperature. Combined with thermal insulation, this approach reduces energy consumption compared to continuous air conditioning while maintaining stable measurement conditions.

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The heating elements proactively raise the CMM structure temperature above ambient levels before measurements begin, and thermal insulation maintains this elevated temperature. This preliminary heating action eliminates the need for continuous energy-intensive cooling during operation.

Inventive Principle:
Principle #10Preliminary action

4Temperature

If cooling systems are used, then temperature control is improved, but ease of operation deteriorates due to sensitivity and handling difficulty

Engineering Contradiction:
Improvetemperature controlVSAvoidease of operation
Core Design Contradiction:
TemperatureVSEase of operation

Solution Approach 1:

The invention replaces sensitive cooling systems with simpler heating elements and thermal insulation. This inverted approach achieves temperature control without the sensitivity and handling difficulties associated with refrigerating elements and liquid coolant circuits, significantly improving ease of operation.

Inventive Principle:
Principle #13The other way round (Inversion)

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 system ensures consistent, high-precision measurements independent of ambient temperatures, is energy-efficient, and reduces the weight and maintenance costs of CMMs, making them suitable for portable and handheld applications.

Implementation Method 1

the control unit is configured to receive the temperature values and to control the heating elements based on the received temperature values

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

The temperature sensors are configured to generate temperature values and to transmit the temperature values to the control unit

Methodology Applied
Scientific EffectThermal radiation detection: Thermal Radiation

Implementation Method 3

incorporating passive thermal insulation and air-guiding tunnels for efficient thermal management

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentEP4310441A1Active thermal management for coordinate measuring machines
Publication Date: 2024.01.24 HEXAGON INNOVATION HUB GMBH
  • EP4310441A1 patent drawingFigure 1
  • EP4310441A1 patent drawingFigure 2~3
  • EP4310441A1 patent drawingFigure 4a~4b

AI summary

The invention pertains to a coordinate measuring machine (CMM) for determining at least one spatial coordinate of a measurement point on an object, the CMM (1) comprising a structure comprising a base (40) and a plurality of frame elements (10a-c, 20a-c), wherein a probe head (30) is attached to one of the frame elements and movable relative to the base, wherein the CMM comprises a temperature control system configured to control a temperature of a plurality of frame elements of the structure and comprising a control unit (50), one or more temperature sensors (51), and one or more heating elements (52), wherein the control unit is configured to control the heating elements based on the temperature values received from the temperature sensors.