1.0 TITLE: ADVANCE MANUFACTURING (PRODUCT QUALITY)

2.0 OBJECTIVE

i. to understand the working principle of coordinate measuring machine and rapid

prototyping machine

ii. to investigate the percentage of machining error

iii. to identify the parameter of the product specimen that being produce by different

machine

iv. to analyses the better process in producing a product

3.0 INTRODUCTION

RAPID PROTOTYPING

Rapid prototyping is a process that being used to fabricate a model of an assembly by three

dimensional computer aided design (CAD) data. Rapid prototyping is a process that uses to

fabricate a product using three dimension computer aided design (CAD) data. The first step

in this process is to draw a 3D model by using CATIA and the drawing being saved in stl

(standard translation language) format. The shape of the drawing that being draw is as

follow.

After the drawing being save in the stl file, the error of the file could be checked by using

magic software and any error can be check by the software before submit the file to the rapid

prototyping machine. Then the specimen was put in the freezer to shorten the time taken by

the specimen to harden. Then the specimen were put in the oven to remove the wax that

over the specimen and only leave the acrylic plastic. For the finishing process the specimen

were immerse in the warm water to produce the final product. The specimen that has been

produce were evaluated with the other product that being produce by using other process.

STANDARD TESSELLATION LANGUAGE

Standard tessellation language or known as stl format file is the file that store three

dimension object data. The purpose of this type of file format is for the moving object through

different software and for 3D printing and computer aided manufacturing. It only described

the surface geometry of the product without any other detail as colour texture or other

common CAD attribute. This type of file was created in order to make it easier for the human

work because this type of data can be read by much software because the 3 dimension

object needs to be move through different software for certain purposes. As example for the

purpose of 3D printing as known the 3D object that being drawn by the CAD software was in

the different format so that stl format file was created to standardize between the different

software.

COORDINATE MEASURING MACHINE

Coordinate measuring machine or known as CMM is a machine that being used to measure

the physical properties of an object. This machine is created in order to provide precise

measurements of object. There is also various type of this machine which available in wide

range of sizes and also in variety of design. There are two available options in handling this

machine that is by manually of automatically control by a computer. This machine work by

the command that being put in the computer. The modern type of this machine has come up

with several advances function such as crash detection system which covers delicate

measurement hardware. This machine used a touch probing method to digitalize coordinates

on a work piece. To use this machine, the axis x, y and z must be set so that the machine

can measure the physical properties of the work piece correctly.

4.0 APPARATUS

Rapid Prototyping Process

Rapid Prototyping Machine

Oven

Glove

Paper

Computer (Magics Software)

Computer (CATIA software)

CATIA software

Magics

Co-ordinate Measuring Process

Scraper tool

TrayProduct from Rapid Prototyping Machine

Co-ordinate Measuring Machine (CMM)

Controllers

Computer (CMM computer controller)

Plaster

CNC cutting work piece

Work piece Flatness table

Laser Cutting work piece

EDM wire cutting work piece

Rapid Prototyping work piece

Pointer

4.1 INDUSTRIAL APPARATUS

Rapid Prototyping Process

Laser Rapid Prototyping Machine

Laser Rapid Prototyping Machine has accuracy in building ±0.1mm. it can support operating

system Windows 98/2000/XP. Furthermore, this machine capable creates an excellent

surface finish.

Rapid Prototyping Machine model MASTER-2011

MASTER-2011 rapid prototyping machine, able to build prototype with maximum speed

30mm/hour. This machine also capable to representing in detail whatever the shape desired.

Co-ordinate Measuring Process

Bridge-type coordinate measuring machine

Bridge-type coordinate machine are build specifically for ease of use. This machine is build

for long-term reliability, thus it suit for industry. It can be control either manually or

automatically. This machine also include with a standard manual displacement.

6 axis 3D measuring arm

6 axis 3D measuring arm is a machine that offer a flexible multi-axis inspection, thus is is

suitable for complex work piece. This machine also has a very high accuracy gauge.

5.0 EXPERIMENTAL PROCEDURE

1. The design of the prototype was draw using CATIA.

2. The file of finalized design was convert using STL (Standard Translation Language)

and Magic Software to detect surface error of prototype before printing.

3. The prototype was print by rapid prototyping (RP) machine for 2 hours 8 minute.

4. Printed design was put in the refrigerator for 5 minute to removed the design from

plate.

5. Next, the prototype was put in the oven for 27 minute.

6. The wax from printed design is removed from acrylic plastic by hot water for 4

minute.

7. The prototype is taken out from the hot water and the excess wax is removed from

the surface of the acrylic plastic.

8. The prototype was moving to metrology lab for inspection by using CMM (Coordinate

Measuring Machine).

9. The Prototype was stick on the stage of CMM using plasticine to prevent any

movement of prototype.

10. The PL (plane), CS and PA was set up on computer and the X-Y-Z coordinates

(0,0,0).

11. The eye ball from CMM is controlled to touched 4 points from prototype (every side).

12. Next, The LN(line) was set up on integrated computer to touch 2 point on each sides.

13. The interception point obtained after IN(intercept) was set up on computer.

14. The dimension was obtains after all the intercept point was mark up to get

dimensions of each sides.

15. CV was set up 10mm/s in order to start measurement for circles.

16. CR was type on the keyboard then AM is activated, and the procedure was continue

for coordinate X and Y=25mm and Z =-2.5 mm.

17. Step 10 until 16 was repeated for another sample of prototype from Rapid

Prototyping, Laser Cutting, EDM cut and CNC Milling.

6.0 RESULT AND DATA ANALYSIS

Types machine

Roundness, (mm)

Diameter circle, (mm)

Percentage error of

diameter circle, (%)

Average of length of

specimen, (mm)

Percentage error of length of specimen,

(%)

Rapid Prototyping

0.0202 29.592 1.360 49.561 0.878

CNC Milling 0.0911 27.946 6.8467 50.008 0.016

Laser Cutting

0.0124 29.977 0.0767 49.872 0.256

EDM Wire Cut

0.0195 29.941 0.1967 50.060 0.120

Percentage error

Rapid PrototypingCNC MillingLaser CuttingEDM Wire Cut

Sample Calculation:

Actual reading in CATIA

Percentage error = |T heory−ExperimentalT h eory |×100%

1. Percentage error of diameter circle.

Rapid prototyping = ¿30−29.592

30∨×100 %

= 1.36%

2. Average of length of specimen.

Rapid prototyping = 49.491+49.551+49.624+49.570

4

= 49.561mm

3. Percentage error of length of specimen.

Rapid prototyping = ¿50−49.561

50∨× 100 %

= 0.878%

7.0 DISCUSION OF RESULT

Rapid prototyping is one of the manufacturing process to create a product design in desired

shape by printing it layer by layer and helps in conceptualization of a design. The difference

with another manufacturing process, the other manufacturing process such as CNC milling,

laser cutting or EDM wire cutting they fabricate the product by subtractive which the form is

shaped by removal material meanwhile for rapid prototyping was vice verse. Below is the

flow chart of rapid prototyping process;

For CMM machine, it one of the computerize device in manufacturing field. The purposes of

CMM machine were to obtain geometry features and object dimension. They precisely

record the dimension in three axis X, Y, and Z. The readings were accumulate by regression

algorithm for the construction. Below is the process of coordinate measuring machine;

For this laboratory, after having rapid prototyping process, we make inspection for the

product by using co-ordinate measuring machine and compare with another manufacturing

process such as computer numerical milling, laser cutting and EDM wire cutting in term of

accuracy in dimension. Regard to the data obtain, rapid prototyping process have the higher

percentage error with 0.878 % compare to others. The most accurate was CNC milling with

0.016 %. For EDM wire cutting, the percentage error was 0.120 % and this was followed by

laser cutting which is 0.256 %. This percentage error was accumulating by make comparism

with CAD drawing in CATIA.

There are a lot of reasons due to the differences of percentage error and one of it was the

process of machining itself. Each process release difference heat when in operation and

cause the product or work piece to bending and when we make inspection with co-ordinate

measuring machine, the result were not accurate. So here we can say that the heat

consume by the work piece effect the percentage error in each process. Moreover, material

uses in each manufacturing process also affect the result where the higher the melting point

of the work piece, the more accurate the result.

For this experiment, we using fully machine, so the only possible error to occur was

accidental errors. They may be due to estimation of values in smallest graduations on the

instruments or due to inexperience in using machine and procedures, certain type of human

errors, errors resulting from variation in definition, the effect from environmental variations

and errors due to insufficient definition of the measuring system.

Some applications of rapid prototyping machine are for making plastic mold part, casting,

master model, and biomedical tool.

8.0 CONCLUSION

In a nutshell, the objective has been successfully achieved since us able to understand

the working principle of rapid prototyping and coordinate measuring machine. We also can

investigate the percentage of machining error by rapid prototyping and coordinate measuring

machine. By using coordinate measuring machine, we able to identify the parameter of the

product specimen that being produce by different machine which are rapid prototyping

machine, CNC milling machine, laser cutting machine and EDM wire cut machine. The better

process in producing a product is CNC milling machine because the average of length

specimen for CNC milling slightly difference between the actual measurements. The value of

CNC milling is 50.008mm. It look more precise compared other machines. The machine that

had lower value of percentage error of length specimen is CNC milling machine namely

0.016%. The product has a hole that circular shape. It means every machine must do a hole

on the product. The diameter circle of laser cutting machine is 29.977mm. It showed the

laser cutting machine is a better machine to produce circular shape because the value of

diameter circles for laser cutting slightly different with the actual measurement. The lower

value of roundness can influence the percentage error of diameter circle. It can give more

accurate measurement of circular shape of the product.

9.0 RECOMMENDATION

1. Make sure the design from the CATIA is pass through Magic Software before

proceed to next stages in order to prevent any surface error of the prototype.

2. Prototype should not be remove from the oven until the wax surface and acrylic

plastic can be clearly distinguished.

3. Clear surface of acrylic plastic can be seen if the prototype is put enough time, so

that there are no remaining white colours of wax on the surface of acrylic plastic.

4. The prototype should be handle with care to avoid any crack or defects to prototype.

5. Standardize the work piece material for each manufacturing process

10.0 REFERENCES

Pham, D. T., & Gault, R. S. (1998). A comparison of rapid prototyping

technologies. International Journal of Machine Tools and Manufacture, 38(10-11), 1257-

1287.

SERIES, I. L. Rapid Prototyping & Manufacturing Technologies.

Chua, C. K., Leong, K. F., & Lim, C. C. S. (2010). Rapid prototyping: principles and

applications. World Scientific.Kunzmann, H., Trapet, E., & Wäldele, F. (1990).

A uniform concept for calibration, acceptance test, and periodic inspection of coordinate

measuring machines using reference objects. CIRP Annals-Manufacturing

Technology,39(1), 561-564.

National Measurement Institute, (n.d.), Coordinate Measuring Machine, Retview on 9

November 2013 at

http://www.measurement.gov.au/Services/Training/Pages/CoordinateMeasuringMachines.as

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