Question

This is for a VF-30 Bonfiglioli worm drive Gearbox

6.1 Housing

6.2 Worm Gear

6.3 Worm Shaft

For each of the MAJOR components (6.1, 6.2 and 6.3) stated only, analyze and identify the manufacturing processes used to make the component – both primary (bulk shape forming) and secondary (or finishing) processes. Include sub-sub-section as follows for each component:

o 6.1.1 Component Observations: Describe your observations of the physical component which indicate what manufacturing processes were performed. Include an annotated picture with arrows pointing to the features.

o 6.1.2 Manufacturing Process: With supporting literature and research, describe the chosen manufacturing process concisely in detail, noting its advantages and disadvantages – describe it in the context of the gearbox you are looking it, not just generally. Detail the advantages and disadvantages of these processes: Relate the chosen method to the production volume of the gearbox.

o 6.1.3 Material Relationship: Relate to the material and its appropriateness in this manufacturing method (e.g. does it have suitable castability?)

Answer 1

Housing

OBSERVATON	The choice of worm gear housing – cast iron or cast aluminum – influences factors such as size, heat dissipation, and resistance to harsh conditions.
MANUFACTURING PROCESS	The manufacturing process used is the casting. Advantages: Casting has following advantages over other manufacturing process. It can create any complex structure economically. The size of object doesn’t matter for casting. The casting objects have high compressive strength. All structure made by casting has wide range of properties. This can create an accurate object. All material can be cast. It creates isotropic structure. It is cheapest among all manufacturing processes. Composite component can be easily made by casting. Disadvantages: Along these advantages, casting has following disadvantages. It gives poor surface finish and mostly requires surface finish operation. Casting defects involves in this process. It gives low fatigue strength compare to forging. It is not economical for mass production.
MATERIAL REALATIONSHIP	The iron or aluminum is used as cast ability material. Both of the material has really good cast ability. Steel is preferred than aluminum as some properties in steel like Hardanability and Brittleness   helps material to become more resistive.

WORM GEAR

OBSERVATON	The material used for the worm gear drive is the Aluminum or Bronze. Worm gear need to be softer than the worm shaft that why aluminum is used.
MANUFACTURING PROCESS	The worm gear manufactured by using Die Casting. The finishing operation done by the Hobbing process. Hobbing is the gear generation process most widely used in gear cutting. Advantages: The casting insures the shape and size as per requirements. The size of object doesn’t matter for casting. The casting objects have high compressive strength. All structure made by casting has wide range of properties. This can create an accurate object. Hobbing process creates the shape of teeth as like hob or worm. Disadvantages: It gives poor surface finish and mostly requires surface finish operation. Casting defects involves in this process. It gives low fatigue strength compare to forging. It is not economical for mass production.
MATERIAL REALATIONSHIP	Aluminum is not bad for casting. It is good for hobbing while finishing.

WORM SHAFT

OBSERVATON	The material used here will be Hard Steel, Stainless Steel, case hardened steels and tempered steels.
MANUFACTURING PROCESS	The manufacturing process will be Forging. Advantages 1.      Forged parts possess high ductility and offers great resistance to impact and fatigue loads. 2.      Forging refines the structure of the metal. 3.      It results in considerable saving in time, labor and material as compared to the production of similar item by cutting from a solid stock and then shaping it. 4.      Forging distorts the previously created unidirectional fiber as created by rolling and increases the strength by setting the direction of grains. 5.      Because of intense working, flaws are rarely found, so have good reliability. 6.      The reasonable degree of accuracy may be obtained in forging operation. 7.      The forged parts can be easily welded. Disadvantages 1.      Rapid oxidation in forging of metal surface at high temperature results in scaling which wears the dies. 2.      The close tolerances in forging operations are difficult to maintain. 3.      Forging is limited to simple shapes and has limitation for parts having undercuts etc. 4.      Some materials are not readily worked by forging. 5.      The initial cost of forging dies and the cost of their maintenance is high. 6.      The metals gets cracked or distorted if worked below a specified temperature limit. 7.      The maintenance cost of forging dies is also very high.
MATERIAL REALATIONSHIP	Steel is the best material for forging. Steel fulfills the all kind of requirements that require for forging operation. All abilities like hardnability, durability, toughness it has.