EBB 427 (5) Hand Lay Up Hazizan

8/3/2019 EBB 427 (5) Hand Lay Up Hazizan

1/11

1

EBB 427 Application and Technology ofEngineering Polymers (Second Half)

Dr. Hazizan Md Akil

School of Materials and Mineral Resources EngineeringEngineering Campus, USM.

Hand lay-up


2/11

2

Processing Technology

Introduction

Hand Lay-Up

Spray Lay-Up

Filament Winding

Pultrusion

Resin Transfer Moulding (RTM) Pre-Preg


3/11

3

Hand Lay-up

Introduction

Most common method in producing composites partsusing thermosetting resins

Especially for large and bulky structures

At McDonnell Aircraft, 100% of the aircraft compositesare produced by hand lay-up.

The primary methods of automation in hand lay-up relateto computer software

Software is used to generate flat patterns from the layersurface and the ply boundary

Software is also used to find the most efficient nest of cutplies to minimize the scrap


4/11

4

Hand Lay-up

Introduction

In the hand lay-up process, fiber reinforcement ismanually inserted into a single-sided mold.

Resin is forced through the thickness of the fiber matsusing hand rollers, and then excess resin is removedusing squeegees

The part is allowed to cure and then disassembled fromthe mold

Since this process is not typically performed under theinfluences of heat and pressure, simple equipment and

tooling can be employed


5/11

5

Hand Lay-up

Introduction

However, this process is very labor intensive, has high

cycle times, delivers only fair dimensional tolerances andreleases a large amount of volatiles.

The nature of the hand lay-up process may also result inparts with inconsistent fiber orientations, that is, the more

the reinforcement is handled, the more likely strands willseparate from the mat or preform

In an open mould of the hand lay-up process, one skin ismoulded at a time and in the final step, skins, spars, and

core are bonded together Such a sequential process increases the amount of

labour required, increases variability between blades,and slows the rate of production.


6/11

6

Hand Lay-up

Introduction

Hand lay-up is a proven process for constructing

composite turbine blades and other structures, but themethods limiting volume output and part inconsistenciesmotivate research into other modes of manufacturing


7/11

7

Hand Lay-up


8/11

8

Hand Lay-up


9/11

9

Hand Lay-up

Advantage

Widely used for many years.

Simple principles to teach.

Low cost tooling, if room-temperature cure resins areused.

Wide choice of suppliers and material types.

Higher fibre contents, and longer fibres than with spraylay-up.


10/11

10

Hand Lay-up

Disadvantage

Resin mixing, laminate resin contents, and laminate

quality are very dependent on the skills of laminators.Low resin content laminates cannot usually be achievedwithout the incorporation of excessive quantities of voids.

Health and safety considerations of resins. The lower

molecular weights of hand lay-up resins generally meansthat they have the potential to be more harmful thanhigher molecular weight products. The lower viscosity ofthe resins also means that they have an increased

tendency to penetrate clothing etc.


11/11

11

Hand Lay-up

Disadvantage

Limiting airborne styrene concentrations to legislated

levels from polyesters and vinylesters is becomingincreasingly hard without expensive extraction systems.

Resins need to be low in viscosity to be workable byhand. This generally compromises their

mechanical/thermal properties due to the need for highdiluent/styrene levels.

EBB 427 (5) Hand Lay Up Hazizan

Documents

Transcript of EBB 427 (5) Hand Lay Up Hazizan