Micromachine Based Fabric Formation Systems

National Textile Center

Year 8 Proposal

Project No.: F98-S12

Competency: Fabrication

Micromachine Based Fabric Formation Systems

Project Team:

Leader George Hodge Expertise CIM, engineering economics

Email: george_hodge@ncsu.edu Phone:

Name/school/expertise

Members:

William Oxenham, NCSU, spinning technology

Abdelfattah M. Seyam, NCSU, weaving technology

Memis Acar, Loughborough University (England), mechatronics

Severine Gahide, PhD Graduate NCSU

Julie Blickensderfer, Undergraduate NCSU

Objective:

Process improvements have focused on mechanization, automation, and integration based on traditional machine tooling concepts. However, a new type of machine tooling has been developed called microelectromechanical systems (MEMS). MEMS are characterized by being less than a square millimeter in size and include both mechanical and electronic components. Example MEMS applications include sensors for air bags in cars, blood pressure monitors that can be place within the heart, and biosensors for measuring carbon dioxide and oxygen content in blood. Using technology similar to that for electronics manufacturing, actuators, sensors, and motors can now be developed. It is now possible to design equipment with mechanisms that are smaller than the diameter of fibers.

The goal of this research is to develop fundamentally new approaches for processing fibers into textile structures using MEMS technology. Objectives of this research are:

1. Design new manufacturing techniques for textile structures,

2. Identify new applications for textiles, and

3. Improve traditional textile manufacturing.

Relevance to NTC Mission:

This research may lead to new types of fabric forming systems. These new machines may then support some of the futuristic concepts of having a customized product, like clothing, produced in real time on demand. This would put the US industry in a position to gain market share in the machine manufacturing area.

State of the Art:

Introduction

For the last fifteen years, a quiet revolution has taken place and is promising a bright future for most industries including textiles. Microelectromechanical systems (MEMS), also known as micromachines, microstructures or nanotechnology, are characterized by being less than a square millimeter in size and include both mechanical and electronic components [1]. In the most general form, MEMS consist of mechanical microstructures, microsensors, microactuators and electronics, all integrated onto the same chip [7]. Commonly used in telecommunication, automotive and biomedical applications, MEMS could find their way in textiles. Features and limits of existing MEMS will be presented and will lay ground for potential textiles manufacturing processes. Although it is because of the emergence of new fabrication technologies -bulk micromachining and LIGA process (Lithographie Galvanoformung, Abformung)- that MEMS are now so popular, microfabrication technology will not be presented.

What are MEMS?

Micromachines are the merging of sensors, actuators and electronics onto the same silicon substrate. They can not only perform electronics chores like detecting temperature changes, or measuring acceleration but they also can open and close valves smaller than a pinprick [2]. The sensors provide the information about the environment based on electrical, physical, chemical or biological measurements. The electronics process the information derived from the sensors and provide a decision making capability for the system based on the information. The actuators respond to control signals from the electronics and manipulate the system or environment for a desired outcome or purpose [6].

Micromachines are divided into two functional groups: the sensors and the actuators, the latter being further divided into three categories:

simple actuators that move valves or beams using one simple physical law
micromotors, more complex in the design and the possibilities, and
microrobots which are the latest release in microtechnology and by far the most fascinating.

There are several technologies available to linearly actuate simple beams, microvalves [6], or diaphragms. When combined together, these microstructures are called micromotors. Microrobots are just the most complicated combination of several micromachines and they are now no longer science fiction but a great reality. The following table is a tentative summary of microtechnologies available in actuators field.

Driving principle	Actuators	Response Speed	Force	Voltage	Comments
Static electricity [4]	Electrostatic rotary motor	medium high	small 5 gf	high 5 to 500 V	Problem of how to fetch output
	Electrostatic linear motor	high	medium	high 5 to 500 V	Suitable for vibrating motion
Piezo electricity [3]	bimorph	medium 1kHz	medium 10 gf	high 10 to 200 V	Large creep and hysteresis present
	supersonic motor [8]	small to medium	large	high 5 to 100 V	Limited miniaturization Heat dissipation necessary
Heat	SMA [3]	medium [8]	large	low to 5V	Heat dissipation problem
	Bimetal	medium	small	low to 5V	Heat dissipation problem
Electromagnetic induction	Ordinary motor	medium to high	small to medium	low	Limited miniaturization due to decreased magnetic flux density
	Super conductive [5]	medium to high	small	low	Low temperature cooling needed No friction problem

Table 1: Comparison of microactuators

Shape Memory Alloy (SMA) and magnetostrictive are just two examples among others, of how a simple physical phenomenon is used to actuate a micromachine. Additional details and examples are found in the NTC 1998 Annual report for this project.

References:

1- Benson, B.; Sage, A.; Cook, G., "Emerging Technology-Evaluation Methodology: with Application to Micro-electromechanical systems", IEE Transactions on Engineering Management, Vol. 40, No. 2, May 1993, pp114-123.

2- Carey, J., "Mighty Mites Hit it Big", Business Week, April 26th, 1993, pp 92-94.

3- Dariot, P.; Valleggi, R.; Corrozzat, W.C.; Coccot, M., "Microactuators for microrobots: a critical survey", Journal of Micromechanics and Microengineering: Structures, devices, and Systems, Vol. 2, Spet., 1992, pp141-157.

4- Fang, J; Gao, R; Rao, B; Warrington, R., "Miniaturized Surface- Drive Electrostatic Actuators: Design and Performance Evaluation", IEEE/ASME Transactions on Mechatronics, Vol.2, No. 1, March, 1997, pp.1-7.

5- Fujita,H., "Studies of Microactuators in Japan", Proceedings of the IEEE International Conference on Robotics and Automation, Scotsdale, AZ, May 14-19, 1989, pp.1559-1564.

6- Huff, A. and Mehregany, M., "MEMS-Based research in Integrated Monitoring and Actuation at Case Western University", Micro-fabrication Laboratory Department of Electrical Engineering and Applied Physics (OH), April 1996.

7- Mehregany, M., "An overview of Microelectromechanical Systems", SPIE Integrated Optics and Microstructures, Vol. 1793, 1992.

8- Muller, R., "Microactuators", http:itri/loyola.edu/mems/ca_s1.htm.

Approach:

During year 1 of this project the following tasks were accomplished.

An initial literature search was completed that identified 50 articles, 30 internet references and 25 R&D centers that focused on MEMS actuators and machines. Previously an assessment of MEMS technology had been conducted by Hodge which identified possible applications in spinning, weaving, knitting, fiber formation, dyeing and finishing and nonwovens (ISA Textile conference June 1997).
An assessment of actuator and sensor technologies has been conducted. Also, the physical and mechanical characteristics of fibers were reviewed. Based on this assessment basic design principles for new MEMS technologies were identified.
A computer aided design system was installed that assists with new product development. Group members were trained on the use of the software.
Group members attended workshops on MEMS technologies on how to utilize the production capabilities at existing R&D labs.
Group members attended national conferences and visited research centers to discuss current applications of MEMS technologies.

This Year’s Goal:

For year 2 the goals of this project are:

To develop concepts for several potential MEMS applications
To evaluate the feasibility and economics of such applications
Based on the above considerations, to identify the application likely to gain widest acceptance by the industry
To start the development of a prototype for this MEMS application

Outreach to Industry:

This research could lead to the development of new means for fabric manufacturing and new products. Input from industry would be sought to identify future characteristics and applications of fabrics. Textile equipment manufacturers would also be contacted to assess new developments in fabric formation systems and opportunities for applying MEMS technologies.

New Resources Required:

Resources for manufacturing MEMS prototypes would be required. These services are available for a fee through the Department of Energy National Labs and other research organizations. In year 2 of the project we would form cooperative services agreements for developing prototypes. The facilities of Textile Technology Laboratory at NCSU College of Textiles would also be utilized.