Plan for Cast and Shaped Parts.


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Rev. 11-2001. 2 of 69. Outline for Cast and Molded Parts. Update Team: Seamus ClarkScott LeonardiGary Meyers. Rev. 11-2001. 3 of 69. Address Topics. Fundamental Casting Design GuidelinesInjection Molding ProcessGating ConsiderationsCase Study
Transcripts
Slide 1

Plan for Cast and Molded Parts Team: Terese Bertcher Larry Brod Pam Lee Mike Wehr

Slide 2

Design for Cast and Molded Parts Revision Team: Seamus Clark Scott Leonardi Gary Meyers

Slide 3

Lecture Topics Basic Casting Design Guidelines Injection Molding Process Gating Considerations Case Study – Corvette Brake Pedal Case Study – M1 Abrams Tank

Slide 4

Lecture Topics Basic Casting Design Guidelines Injection Molding Process Gating Considerations Case Study – Corvette Brake Pedal Case Study – M1 Abrams Tank

Slide 5

Basic Casting Design Guidelines Visualize the Casting Design for Soundness Avoid Sharp Angles & Corners Minimize the Number of Sections Employ Uniform Sections Correctly Proportion Inner Walls Filet All Sharp Angles Avoid Abrupt Section Changes Maximize Design of Ribs & Brackets Avoid Using Bosses, Lugs & Pads

Slide 6

Visualize the Casting It is hard to take after area changes and shapes from outline. Make a model to scale or full size to help fashioner to: See how centers must be planned, put or excluded Determine how to shape the throwing Detect throwing shortcomings (contracts/breaks) Determine where to place entryways and risers Answer questions influencing soundness, cost and conveyance

Slide 7

Simplification of Die Configuration

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Simplification of Die Configuration

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Simplification of Die Configuration

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Simplification of Die Configuration

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Design for Soundness Most metals and combinations shrivel when they cement Design segments with the goal that all parts increment in measurement logically to ranges where feeder heads (risers) can be put to counterbalance shrinkage. Mask zones of shrinkage when unavoidable

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Design Rules: Disguising Sink Marks

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Avoid Sharp Angles & Corners When at least two segments conjoin, mechanical shortcoming is instigated at the intersection and free cooling is interfered with – most normal imperfection in throwing plan. Supplant sharp edges with radii and minimize warmth and stress focus In cored parts maintain a strategic distance from outlines without cooling surfaces An adjusted intersection offers uniform quality properties

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Incorrect Corner Design Good Corner Design Generous span Uniform divider thickness Smooth stream move Very sharp radii High anxiety fixation Sharp stream move Incorrect Corner Design Incorrect Corner Design Outside corner and inside range Non-uniform divider thickness Non-uniform stream move Shrinkage stretch/voids/sinks Inside/outside sweep crisscross Non-uniform divider thickness Non-uniform stream move Sink Design Rules:Corners & Radii

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Minimize the Number of Sections An all around composed throwing brings the base number of segments together at a certain point. Amazing segments (where conceivable) Minimizes problem area impacts Eliminates shortcoming Reduces contortion Where stunning areas is impractical utilize a cored opening through the focal point of the intersection. Speeds cementing Helps to maintain a strategic distance from problem areas

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Employ Uniform Sections Thicker dividers will harden all the more gradually. This implies they will bolster cementing internal dividers. Brings about shrinkage voids in the thicker dividers Goal is to configuration uniform segments that cement equitably. In the event that this is impractical, every overwhelming area ought to be available to encouraging from risers.

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Improved Part Design Thinner divider segments More uniform divider thickness Inside and outside radii (when conceivable) Original Part Design Very thick divider segments Non-uniform divider thickness Sharp inside and outside radii Design Rules: Wall Uniformity

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Correctly Proportion Inner Walls Inner areas of castings cool much slower than external segments. Causes varieties in quality properties A decent general guideline is to decrease internal segments to 90% of external divider thickness. Maintain a strategic distance from fast area changes Results in porosity issues like what is seen with sharp edges.

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Part gated from "thin to thick" upsets pressing of thicker areas and can make stream issues. Inner runner to help/enhance the capacity to pack the thick segment when gating from "thin to thick" is vital. Gating from "thick to thin" when conceivable to enhance stream and permit thicker areas to be pressed. Configuration Rules: Wall Uniformity

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Correctly Proportion Inner Walls Whenever complex centers must be utilized, outline for consistency of segment to maintain a strategic distance from nearby substantial masses of metal. Within distance across of barrels and bushings ought to surpass the divider thickness of castings. At the point when the I.D. is not exactly the divider it is ideal to give the segment a role as a strong. Openings can be created by less expensive and more secure strategies than with amazingly thin centers

Slide 21

Filet All Sharp Angles Filets (adjusted corners) have three useful purposes: To lessen the anxiety focus in a throwing in support of dispose of breaks, tears and draws at reentry edges To make corners more pliant by taking out problem areas The quantity of filet radii in one example ought to be the base conceivable.

Slide 22

Filet All Sharp Angles Large filets might be utilized with radii approaching or surpassing the throwing segment. Ordinarily used to satisfy building stress prerequisites Reduces stretch focus Note: Filets that are too substantial are undesirable – the span of the filet ought not surpass a large portion of the thickness of the area joined.

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Filet All Sharp Angles Tips to keep away from an area size that is too expansive at a "L", "V" or "Y" intersection. For a "L" intersection : Round an outside corner to coordinate the filet within divider. (On the off chance that this is impractical the creator must settle on a choice as to which is more critical: Engineering outline or conceivable throwing imperfection) For a "V" or "Y" intersection: Always plan so that a liberal span takes out restriction of warmth.

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Design Rules: Filets & Corners

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Avoid Abrupt Section Changes The distinction in relative thickness of abutting areas ought not surpass a proportion of 2:1. With a proportion under 2:1 the adjustment in thickness may go up against the type of a filet. Where this is unrealistic consider a plan with separable parts.

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Avoid Abrupt Section Changes With a proportion more noteworthy than 2:1 the suggested move for the adjustment in thickness ought to go up against the type of a wedge. Note: wedge-molded changes in divider thickness ought not decrease more than 1 in 4. Where a blend of light and substantial segments is unavoidable, utilize filets and decreased areas to temper the movements.

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Tapered Transition Better Wall Thickness Transitions Gradual Transition Stepped Transition Poor Design Best Core out thicker ranges where conceivable Design Rules: Section Changes

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Maximize Design of Ribs & Brackets Ribs are just best when the throwing divider can\'t be made solid or sufficiently hardened all alone. Ribs have two capacities: They increment firmness They lessen weight Common oversights that make ribs ineffectual: Too shallow Too generally separated

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Maximize Design of Ribs & Brackets The thickness of the ribs ought to be roughly 80% of the connecting thickness and ought to be adjusted at the edge. The plan inclination is for ribs to be more profound than they are thick. Ribs ought to harden before the throwing area they border. The space between ribs ought to be outlined to such an extent that confined collection of metal is anticipated.

Slide 30

General Guidelines for Rib Dimensions * Component divider thickness: h Draft per side(0): 0.5 º  1.5º Rib tallness (L):  5h (commonly 2.53.0h) Rib dispersing (on focus):  2h  3h Base range (R):  0.25h  0.40h Rib thickness (t): 0.4  0.8h *Exact rib measurements are material particular Design Rules:Rib Dimensions

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Shrinkage Voids Excessive Radius Rib Sink Mark Radius (filet) Part Wall Excessive Rib Wall Thickness Correct Proportions Design Rules:Rib Wall Thickness

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Maximize Design of Ribs & Brackets Generally, ribs in pressure offer a more prominent security figure than ribs strain. Exemption: Castings with thin ribs in pressure may require configuration changes to give vital hardening and abstain from clasping. Thin ribs ought to be evaded when joined to an overwhelming area or they may prompt to high burdens and splitting

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Maximize Design of Ribs & Brackets Avoid cross ribs or ribbing on both sides of a throwing. Cross ribbing makes problem areas and makes nourishing troublesome Alternative is to configuration cross-coupled ribs in an amazed "T" shape. Stay away from complex ribbing Complicates forming, blocks uniform cementing and makes problem areas.

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Maximize Design of Ribs & Brackets Ribs meeting at intense points may bring about embellishment troubles, increment costs and disturb the danger of throwing imperfections. "Honeycombing" regularly will give expanded quality and firmness without making problem areas.

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Design Rules: Rib Manufacturability

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Design Rules: Rib Design

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Maximize Design of Ribs & Brackets conveying counterbalance loads present bowing minutes limited and in the body of the throwing. Tips to stay away from this issue: Taper "L" molded sections and reach the primary giving a role as sufficient as would be prudent. Sections may every now and again be thrown independently and after that joined, improving the trim.

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Maximize Design of Ribs & Brackets A ribbed section will offer a firmness advantage, however stay away from warmth fixation by giving cored openings in networks and ribs. The openings ought to be as expansive as could be allowed The openings ought to be reliable with quality and firmness Avoid rectangular-molded cored gaps in ribs or networks. Utilize oval-molded openings with the longest measurement toward the anxieties

Slide 39

Sharp corners, little radii H  T H > T center out underside Ribs inside, g

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