Manufacturing Processes Chapter 40

Define manufacturing engineering.

Manufacturing engineering is a technical staff department responsible for planning the manufacturing processes for a product and its components.

What are the principal activities in manufacturing engineering?

Principal activities in manufacturing engineering are (1) process planning, (2) technical problem solving and continuous improvement, and (3) advising the product designers in design for manufacturability.

Identify some of the details and decisions that are included within the scope of process planning.

Table 40.1 lists the following details and decisions in process planning: (1) the processes required and the sequence in which they are performed; (2) equipment selection; (3) tools, dies, molds, fixtures, and gages that will be needed; (4) cutting tools and cutting conditions for machining operations; (5) methods for manual operations (e.g., assembly) and manual portions of machine cycles (e.g., loading and unloading a production machine); (6) time standards for each operation; and (7) estimates of production costs. Not all of these details and decisions are the exclusive responsibility of the manufacturing engineering department.

Name three of the general principles and guidelines in design for manufacturability.

Table 40.5 lists the following DFM principles and guidelines: (1) Minimize number of components. (2) Use standard commercially available components. (3) Use common parts across product lines. (4) Design for ease of part fabrication. (5) Design parts with tolerances that are within process capability. (6) Design the product to be foolproof during assembly. (7) Minimize flexible components. (8) Design for ease of assembly. (9) Use modular design. (10) Shape parts and products for ease of packaging. (11) Eliminate or reduce adjustment required.

Identify some of the important factors that should enter into the make or buy decision.

The factors in the make or buy decision include (1) cost, (2) whether the process is available internally, (3) production quantity, (4) product life, (5) whether or not the component is a standard commercially available hardware item, (6) supplier reliability, and (7) possible need for alternative sources.

Which of the following are the usual responsibilities of the manufacturing engineering department (four best answers): (a) advising on design for manufacturability, (b) facilities planning, (c) marketing the product, (d) plant management, (e) process improvement, (f) process planning, (g) product design, (h) solving technical problems in the production departments, and (i) supervision of production workers?

(a), (e), (f), and (h).

Which of the following are operations to enhance physical properties (three correct answers): (a) annealing, (b) anodizing, (c) die casting, (d) drilling, (e) electroplating, (f) rolling of nickel alloys, (g) sheet metal drawing, (h) sintering of pressed ceramic powders, (i) surface grinding of hardened steel, (j) tempering of martensitic steel, (k) turning, and (l) ultrasonic cleaning?

(a), (h), and (j).

In a make or buy situation, the decision should always be to purchase the component if the vendor's quoted price is less than the in-house estimated cost of the component: (a) true or (b) false?

(b).

Which one of the following types of computer-aided process planning relies on parts classification and coding in group technology: (a) generative CAPP, (b) retrieval CAPP, (c) traditional process planning, or (d) none of the preceding?

(b).

Which of the following would be considered secondary processes, as opposed to basic processes (four correct answers): (a) annealing, (b) arc welding, (c) drilling, (d) electroplating, (e) extrusion to produce steel automotive components, (f) impression die forging, (g) painting, (h) plastic injection molding, (i) rolling of sheet steel, (j) sand casting, (k) sheet-metal stamping, (l) sintering of pressed ceramic powders, and (m) ultrasonic machining?

(c), (e), (k), and (m).

Which of the following are considered basic processes, as opposed to secondary processes (four correct answers): (a) annealing, (b) anodizing, (c) drilling, (d) electroplating, (e) forward hot extrusion to produce aluminum bar stock, (f) impression die forging, (g) rolling of sheet steel, (h) sand casting, (i) sheet-metal stamping, (j) spot welding, (k) surface grinding of hardened steel, (l) tempering of martensitic steel, and (m) turning?

(e), (f), (g), and (h).

A route sheet is a document whose principal function is which one of the following: (a) continuous improvement, (b) design for manufacturability, (c) provides authorization for material handlers to move the part, (d) quality inspection procedure, (e) specifies the process plan, or (f) specifies the detailed method for a given operation?

(e).

The manufacturing engineering department in an organization is best described as which one of the following: (a) branch of the sales department, (b) concurrent engineers, (c) management, (d) product designers, (e) production supervisors, or (f) technical staff function?

(f).

What is the difference between a basic process and a secondary process?

A basic process establishes the starting geometry of the work material; e.g., casting, rolled sheet metal, drawn metal bar. Secondary processes are used to refine the starting geometry and transform the material into final shape and size; machining and sheet metal pressworking are common secondary processes.

What is a precedence constraint in process planning?

A precedence constraint is a limitation on the order in which processing or assembly operations can be performed on a given workpart; for example, a hole must be drilled before it can be tapped.

What is a route sheet?

A route sheet is a listing of the production operations and their sequence required to make a given part. It also lists the equipment and special tooling that is required.

In the make or buy decision, why is it that purchasing a component from a vendor may cost more than producing the component internally, even though the quoted price from the vendor is lower than the internal price?

Because purchasing the component may cause idle equipment and staff in the factory that the company must still pay for.

What is concurrent engineering and what are its important components?

Concurrent engineering is an approach used by companies to reduce the time to bring a new product to market. It includes (1) design for manufacturability, (2) design for quality, (3) design for life cycle, and (4) design for cost. It also includes certain organizational changes that attempt to bring different functions in the company together during product design to consider all possible aspects of the product.

What is meant by the term design for life cycle?

Design for life cycle means that factors relating to the product after it has been manufactured should be taken into consideration in design. These factors include ease of installation, reliability, maintainability, serviceability, upgradeability, and disposability.