Manufacturing process selection and Design for manufacturing

Apply a systematic process selection approach, screening and ranking options by design requirements, material availability, geometry, size, tolerances, surface finish, cost, lead time, tooling, and quality criteria.

Explore a simple process-material compatibility matrix to screen suitable manufacturing methods for ferrous and non-ferrous materials, including sand casting, extrusion, machining, sheet forming, and molding.

Explore shapes of engineering parts and how manufacturing process selection aligns with part geometry, from prismatic and non cylindrical prismatic forms to sheet metal and complex solid 3D components.

The process shape matrix guides selecting manufacturing processes by geometry, showing which processes can produce prismatic, cylindrical, 3D solid, or hollow parts, including casting, forging, machining, molding, and sheet forming.

Understand how section thickness governs manufacturing process selection, comparing practical thickness ranges across sand casting, investment casting, forging, extrusion, sheet metal forming, injection molding, and machining.

Examine tolerances and dimensional accuracy in mechanical design, where small deviations can threaten product safety. Identify inherent process variations, cost implications, and how design features influence tolerances.

Explore how tolerance ranges differ across sand casting, other casting methods, forging, extrusion, sheet metal forming, and machining, and how surface roughness and finishing processes affect aesthetics and fatigue life.

Analyze raw material costs and wastage, tooling and equipment investment, and processing costs (setup, labor, machine operation, post processing, energy) that drive manufacturing process selection and design decisions.

Explore the cost model for manufacturing: how materials, investment, time, energy, parts, and information drive product cost and price, and how design for manufacturing and assembly optimizes margins.

Compare the costs of sand casting, die casting, forging, sheet metal forming, machining, and injection molding, highlighting upfront investments, tooling costs, and economies of scale for high-volume production.

Explore how sand casting and die casting compare in cost per component as volume grows, with tooling costs dominating at low volumes and die casting becoming cheaper at higher volumes.

Compare how part complexity affects cost in sheet metal and plastic injection molding, noting cheaper sheet metal for simple geometries and faster cost growth with complexity.

Explore how prototyping verifies design function, durability, and safety before mass production. Learn low-cost methods like cnc machining, 3d printing, sheet metal fabrication, and thermoforming used in early-stage development.

Compare 3d printing and injection molding for manufacturing decisions; 3d printing suits prototyping with no tooling and constant per-part cost, while injection molding scales with volume and lower unit costs.

Learn process selection criteria that balance functional performance, quality, and economics; adjudicate material, size, shape, wall thickness, tolerances, and surface finish to optimize lead times, part cost, and production quantity.

Analyze a steering column mount bracket design: select aluminum for stiffness and light weight, and evaluate machining, forging, sand casting, and die casting for high-volume auto production, favoring die casting.

Case study 2 analyzes a stepped shaft with a keyway for machinery, requiring high strength and fatigue resistance with tight tolerances. Machining in steel is favored over aluminum and plastic.

Examine the shifter fork in an automotive transmission, compare aluminum and steel for weight and strength, and decide die casting is preferred for high-volume production when stress levels allow.

We examine the Ford steering knuckle as a high-load, multi-directional structural member mounted to the wheel hub, noting fatigue and impact loading and favoring lightweight aluminum with casting.

Explore case study 6: brake line bracket for mounting a brake line on a frame in automotive systems. Compare sheet metal and solid geometry options for a rigid, cost-efficient bracket.

Engage in a hands-on exercise to research a typical manufactured part, compare materials and manufacturing processes, justify the chosen model and process, and explore design improvements.

Explore design for manufacturing to make parts easy to produce by prioritizing practicality, time, cost, and quality. Simplify designs to reduce processing time and defects, guided by DSM guidelines.

design for manufacturing and concurrent engineering encourage early involvement of manufacturing engineering with the product design team to reduce cost and maximize the impact of changes during part design.

Apply heavy local compression to shape metal by forging, using open-die or closed-die methods like upset and impression-die forging; hot and cold forging yield different properties and density.

Examine the cross section of an impression die forging, detailing the upper die, lower die, die cavity, parting line, and the flow that creates flash into the gutter.

Explore generic forging design principles, including material flow and path of least resistance, and the roles of draft allowances, lay location, and parting line.

Explore how fillet radii and draft angles influence metal flow in forging, preventing cracks and defects by ensuring smooth fill and proper parting from the die.

Explains web depth and thickness in forging, highlighting ribs and webs with depth d and thickness t, and notes steel and titanium constrain depth, aluminum allows deeper webs.

Explore how grain orientation in metals governs local mechanical properties, with forging, machining, and casting showing different strengths, and how symmetric parting lines improve strength by creating balanced grain structures.

explain how side thrust force arises in forging dies from departing lane geometry and inclination, with friction, and show how part orientation and two cavities cancel the thrust.

Compare forging ease across geometries; a solid block is the easiest to forge. Increase difficulty with ribs, taller ribs, and thinner webs, and apply the same principle to circular shapes.

This case study shows how to prepare a forging-ready part from a CAD model using Fusion 360, including parting plane, two halves, drafting and features like web, emboss, and fillets.

Explore a structured workflow from solid geometry to embossing for forging, through three progressively challenging exercises that train drafting surfaces, mid planes, and joining techniques for forging-ready parts.

Explore sand casting fundamentals, including mold cavities, gate and riser systems, cores, and design considerations that ensure unrestricted molten metal flow, uniform cooling, and dimensional accuracy.

Keep wall thickness uniform across casting, limit fillet radii, include drafts, avoid undercuts, use ribs to aid flow, align features to parting line, avoid thin sections, and promote directional solidification.

Explore drafting and cores in casting, understanding draft angles, parting lines, external and internal drafts, and how cores create internal cavities while maintaining mold integrity.

Locating the parting line critically influences mold cavity design, sand flow, ease of part removal, gating layout, mold quality, and final casting size and accuracy.

Compare poor and good design features for casting, focusing on step transitions, uniform wall thickness, fillets, and ribs to improve molten metal flow and stiffness.

Reduce casting complexity by minimizing core cavities through design changes that eliminate undercuts and align cores with the parting line, lowering cost and improving quality.

Identify hotspots as slow cooling regions in casting geometries and apply fillets, uniform wall thickness, and staggered rib designs to achieve uniform cooling and reduce shrinkage and porosity.

Apply a CAD-driven design forecasting workflow to position pour lines and gates, modify geometry for draft and uniform wall thickness, ensure smooth molten flow, and avoid hot spots and defects.

The case study shows converting a CAD part into a castable geometry by applying parting lines, drafts, and fillets, with machining cuts to flat mounting surfaces, using Fusion 360.

Design for machining guides creating simple geometries, minimizing operations, and ensuring tool access for CNC turning and milling, while addressing material machinability, tolerances optimization, and fixturing.

Select materials with high machinability to ensure easy turning, milling, drilling, and grinding, and evaluate tool life, cutting speed, surface finish, power, and chip flow to guide design.

Explore CNC milling and turning as the basis of machining design, focusing on tool geometry, tool access and path, and path setup and workholding.

Keep cavity depth under four times the width, base depth on flute length, and use variable depth across the width to minimize tool deflection, chip evacuation issues, and vibrations.

Explore fillet radius in cnc milling, where vertical fillet radii exceed one third of cavity depth and minimum vertical radius equals 1.3 times the cutter radius.

Determine minimum wall thickness and hole sizes for cnc milling, using 0.8 mm for metal walls and 1.6 mm for plastics, and keep holes at least 3 mm.

Explore how workpiece setups use fixtures and clamping to fix blocks for multiple operations. Minimize setups to reduce time and cost, using three- and five-axis VMC when possible.

Analyze how part design dictates workpiece setups, showing holes, slots, and cavities drive recalibration and cost. Encourage designs that are easier to machine and reduce the number of setups.

Explore undercuts in cnc milling, why standard tools can’t reach deep cavities, and how specialized tools, depth and width guidelines, and pocket clearance shape design for manufacturing.

This case study examines five machining features—fillet, chamfer, rectangular cutout, rectangular through hole, and three cylindrical holes—on a billet with a three-axis vmc, requiring three setups with reorientation and recalibration.

Design for milling promotes chamfers over fillets to reduce machining time and tooling costs, favors cone bottom holes, notes that internal cavities cannot be machined, and multi-curved surfaces take longer.

Explore how corner reliefs in machining enable easy assembly of mating parts by compensating for cutter diameter, with alternatives like corner fillets and design changes when reliefs are not feasible.

Explore basic turning guidelines for CNC turning, including length-to-diameter ratios, wall thickness, and undercuts, and see how long and thin paths, tailstock support, and vibrations influence accuracy and manufacturability.

Design for injection molding guides engineers to ensure smooth molten flow, avoid obstructions and deep cavities, and account for material, pressure, mold temperature, and gating.

Explore the parts of an injection molding die, including primary and secondary runners, the gate, and cavity filling, and how gating and cavity geometry affect part production.

Apply generic design rules for injection molding, including draft angles from 0.5 to 2 degrees, rib design, corner radii, and uniform wall thickness to ensure smooth flow and reduce defects.

Strengthen the core in injection molding to minimize dimensional variations in deep cavities; use a tapered, stepped VCR-type core for rigid support during filling.

Learn how gate location in injection molding governs material flow and uniform cooling across cavities. Place gates centrally near heavy cross sections, and use multiple gates for complex parts.

Explore injection molding of plastics like nylon, polycarbonate, polyethylene, polypropylene, polyurethane, and rigid PVC. Learn how shrinkage causes sinks and warping and how uniform wall thickness and notches counteract them.

Design circular bosses with ribs to maintain uniform wall thickness and cooling, reducing sink marks and warping; position near corners and use proper rib thickness and draft.

Learn how to convert a computer-aided design solid into a plastic injection molded part by applying drafts, fillets, parting line placement, rib features, wall thickness, and rib details.

Practice converting solid CAD geometry to shell forms suitable for injection molding, applying drafts, ribs, and bosses while maintaining wall thickness up to 3.5 mm.

Explore manufacturing process selection and design for manufacturing within the broader mechanical design process, covering idea generation, product planning, development, architecture, material selection, and sheet metal design.