Sterling Engine

1.0 – Introduction

Manufacturing is basically the production of merchandise using machines and labour converting raw materials into finished goods that achieve a previously expectation or specification. The fabrication process used in the item manufacture shall be taken into consideration in the creative process of parts (new designs) in order to check the feasibility of it.

For the manufacture of parts many different processes can be used depending on a several factors, such as, material to be used, quantities of parts to be manufactured, expected costs, initial investment (in case of tools) and so on, some of those ways can be better or worse.

At this report, which will be divided in two parts, will be shown the work made at the Manufacturing module of Anglia Ruskin University.

Firstly it will be described the safety procedures taken at the workshop in order to prevent accidents, moving on will be discussed about the workshop lectures where the Stirling Engine components were manufactured and the final product assembled and then to conclude the first part the whole design would be evaluated and changes to improve the manufacturing processes will be listed.

Secondly, the Flat Bottle Opener design will be shown with all the detailed specification such as, material used, fabrication process to manufacture and safe procedures. To conclude the staged involved in the manufacturing process will be discussed.

2.0 - Safe use of workshop facilities

Working in a machining workshop can offer several possibilities of accidents or damages if the right precautions are not taken. There are thousands of people injured, or even killed, through work each year. HSE (2009) statistics “show that contact with moving machinery was responsible for significant numbers of injuries and fatalities in the manufacturing industries alone. Not all of these will have involved workshop machinery, but the figures nevertheless highlight how dangerous machinery can be: 1542 out of 15,047 over-three-day injuries (10%); 599 out of 4,015 non-fatal major injuries (15%) and 2 out of 23 fatalities (9%).

As is possible to see in the statistics above the machining workshop work requires some attention related with the safe procedures. Indeed, the machines and tools used usually have sharp edges and can be heavy. Moreover, due to the energy involved in the machining, is natural to have chips flying or spread in the workshop. Those chips can easily hurt a person because they are hot and commonly sharp.

However, on the other hand of all these problems, there are solutions to be taken. First of all the most important aspect to avoid the majority of risks is the behaviour and the conduct in the workshop. Is substantially important be careful and pay attention in all the steps and procedures made in the machine. Furthermore, use the tools correctly and never work feeling sleepy or alcohol or other drugs influence is essential.

In addition, wear appropriate clothes during the workshop, such as boots designed to protect the foot against heavy or sharp things, glasses to protect eyes against chips of the work piece and wear lab coat to avoid burns can reduce substantially the number of accidents.

3.0 - Part 1, Dolly Sterling engine

3.1 – Stirling engine - evaluation of the design

The product manufactured in the workshop classes is called “Dolly 1” and it is an engine model which works with air in different temperatures. According with Helman (2014), “the device in its simplest form consists of applying an external heat source to a closed cylinder where the cyclical expansion and compression of air inside the cylinder drives the pistons up and down … the Stirling is an external combustion engine; it can work with any external heat source.” In other words, the operation consists basically in a cycle that does not suffer exhaust or intake, however heating source at one end of the cycle, resulting in a pressure that forces the piston out and in the opposite side the same amount of air is cooled, producing a vacuum that forces the piston back.

This engine has a simple design and it does not have too many components, however, the model manufactured in the workshop classes offer the opportunity for the students work in different machines and by this fact ken different fabrication processes, tools and materials. In the Figure 1 bellow, is possible to see the final product.

Figure 01 – Stirling Engine manufactured in workshop classes.

3.1.1 – Hand working

The power and displacer conrods and the flywheel shaft were made by hand working, as a result the finishing was not plentiful smooth and the dimensions not as accurate as the parts made by automated processes, however, only the distance between the two holes and the size of them had to be precise. Other common machine used to create holes was the milling machine which after positioning offers precision.

3.1.2 – Turning Machine

The bush, displacer flywheel, power flywheel, power cylinder, power piston, displacer guide, shaft, gudgeon block, flywheel shaft, displacer, cap, heat sink and end cap were all made by the turning machine. To operate this machine and get the accurate dimensions some initial procedures need to be taken. Firstly, set the right RPM speed depending on the material to be machined and the finish