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Piston Manufacturing

PREPARED FOR PROF. JASON FLOOR

PREPARED BY

Rajan Bawa

MET 514 CNC COMPUTER PROGRAMMING ARIZONA STATE UNIVERSITY

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CONTENT

CONTENT

1. INTRODUCTION……………………………………………………………………….3

2. PISTON………………………………………………………………………………….4

2.1 3D IMAGE OF PISTON…………………………………………………….4

3. METHODOLOGY………………………………………………………………………5

3.1 MATERIAL………………………………………………………………………….6

3.2 STOCK……………………………………………………………………………..6

3.3 OPERATION 1…………………………………………………………………….7

3.4 INSPECTION 1……………………………………………………………………8

3.5 OPERATION 2…………………………………………………………………….9

3.6 INSPECTION 2……………………………………………………………………11

4. RESULLTS……………………………………………………………………………..12

5. CONCLUSION………………………………………………………………………….14

REFERENCES………………………………………………………………………………….1

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Introduction:-

This CNC project is designed to help student develop a technical

understanding in machining a component using 3-axis and 5- axis setup. The

part that will designed in this process is Piston which is made of aluminum

and will require different operations such as holes, fillets, grooving and

chamfers. Tools such as Simulation of Piston using HSM solid work, a CNC

3- axis and 5-axis machine, a band saw and measurement equipment.

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Piston:-

Piston is a major component in reciprocating engines, pumps and gas

compressors that transfer the force of the expanding gases to the crankshaft

by means of the connecting rod. Piston is connected to the connecting rod via

wrist pin. To visualize the piston in 3D frame, the animation is used in this

project.

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Methodology: -

The piston is designed using two set of operations. Both the operations are

performed on different machine in order to ensure quality work. Most of the

general processes can be described using product routing as it will list the

operational description, tooling and machine operation. Not only product routing

organizes the steps involved but also tells us how the parts are produced in the

manufacturing setup.

The CNC processes are divided in such a way that after each set of operation,

part is inspected to ensure that part is ready for the next operation. This

inspection steps are important as they tells us about the last outcome that we will

receive after coming the above task.

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The Inspection process just make use of dial caliper’s, Micrometer and simulation

of the part using HSM solid works. The process will not make use of CMM lab for

computing the dimensions set for the part.

Material:-

The material chosen for piston for this operation is 6061-T6AL. Most of the

pistons are made either of cast iron or of Aluminum alloy. The advantage of using

the aluminum alloy over cast iron is that aluminum has high thermal conductivity

that results in less variation in temperature from crown to piston rings. Moreover,

piston designed using AL is a light weight construction with minimum inertia

force.

Stock: -

The most important thing to consider while cutting the stock is that it should be

larger than the part that will be obtained after machining. The dimensions for a

cylindrical stock is having a length of 2.1” inch and diameter of 3” inch. The

machine that will be used for cutting operation is Horizontal Band Saw machine.

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Operation 1: -

This operation will make use of H-Haas Lathe

machine to accomplish the following tasks.

To program the G-codes, it gets necessary to

use HSM extension, the operation will involve

two set of work each on different face. This

operation will require following task: two co-

ordinate system for facing each top part, groove

cutting and finally fillets across the edges. The figure will illustrate how the part

should look like after operation 1.

Figure 2. Part after operation 1.

Source: student

Figure 1.

Operation involved

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Each procedure follows an inspection test to verify the outcomes and results

obtained. The test involve measure of the part dimensions, tolerances on

drawing. The tool required to carry out such test include dial caliper and

micrometer. The results of the first inspection are summarized as follow:-

Table 2. Summarize the results for the first inspection:-

Inspection for OP #1

Source: Student

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Operation 2

1. Operation build for Operation 2: -

The second operation is complex as it will involve number of operation which

includes 2D counter, Pocket milling, boring and chamfering like process. The

Machining time taken for second operation was near to 25.45 minutes. The

operation is designed on 5-axis CNC machines. The figure 3 will illustrate the

kind of machine setup we had for OP#2.

Figure 3:- 5-axis machine setup

Source: Student

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The work-piece is clamped using 3-jaw chuck tightly and precisely. But the care

was taken part is not subjected to any over pressure. The figure 4 illustrates the

dimensions and how the final product should look like after OP#2.

Figure 4. Piston after OP#2

Source: - Student

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Inspection#2

Table 3 is used to summarize most part information. The inspection was carried

using same tools as used in operation 1.

Table 3. Inspection for OP#2

Source: Student

The fillet radius can be measured using radius gauge and the curved surface can

be inspected well using CMM inspection.

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Results:-

Figure 5 represent the part after operation 2. Deburring tool is used by the end of

each operation. The process helps in removing the extra material or raised edges

left after machining.

Figure 5. Final Part after OP#2

Source: Student

The challenging part of designing this Complex geometry can be associated with

code generation and co-ordinate system designed for each job. The part got very

well machined accept the minor problems of burring over edges.

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Figure 6 presents the imperfection associated with piston design. The incorrect

diameter of the hole makes it impossible for the wrist pin to fit in the piston.

Figure 6 Imperfect Hole diameter

Source: Student

The most important feature in piston are related to its holes, diameters, grooves

and pocket width. This because piston is assembled with wrist pins, piston rings

and connecting rod which not only help transfer the force associated with

expansion of gasses but also the distribution of heat through it.

In Table 3 we present to you the measures of hole, this dimension is critical as

this is the means to connect piston with the connecting rod via wrist pin. Nother

important measure is pocket width. Not that critical dimension, that slight

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imperfection will affect the overall efficiency but will have effect on the functioning

of piston rod assembly.

Conclusion: -

The piston manufacturing using 3-axis and 5-axis was helpful in practicing

several tool of 2D, 3 axis and 5 axis programming. The machine setup and

control panels introduces new ways to complex shapes which require practice for

skill to come along. All in all project throws light on new concepts which were

untouched earlier.

References:-

1. Use of Wikipedia in extracting some information on Piston, wrist pin,

deburring and other things.

2. You tube videos on how to form an engineering drawing based on the part

machined in solid works.

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