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What’s new in DFMPro v5.2 for Creo Parametric

The latest release of DFMPro for Creo introduces additional rules with promising benefits for users of organizations dedicated to (or, using) assembly and manufacturing processes like Die Casting, Injection Molding and Sheet Metal.

Following Rules are added:

Assembly Rules:

1. Bolt and Screw Rationalization:

Optimizing the head type is another way for rationalization. If the application allows the same head type to be used throughout then it will help to reduce time, labor and cost.

Bolt and Screw Rationalization

Fig 1: Bolt and Screw Rationalization

Benefit: Rationalization of fasteners/hardware saves huge cost to organization. Identifying such fasteners in assembly design and taking appropriate action to rationalize among them will help to reduce the assembly cost drastically.

2. Preferred Hardware:

Hardware preference is done with the purpose of making a product available with various features at different costs based on market demand.

Benefit: Preferred hardware will improve usage of the standard fastener library which enables design and engineering teams to understand the preferences from sourcing to maintaining lower costs for commodity items.

3. Recommended Bolted Joints:

Too many fasteners lead to situations where excessive time is spent in assembly procedures, excessive cost is expended drilling and tapping holes and increased quality issues are entered into with increased number of potential mistakes with bolt selection.

Recommended Bolted Joints

Fig 2: Recommended Bolted Joints

Benefit: This is done with a purpose of making the product available with various features at different costs based on market demand.

4. Slot To Hole Alignment:

Hole should be collinear and be at the center of a slot. Hole to slot positioning is a position of the slot with respect to the thread hole with the adjacent part. This should measure the slot position center to the thread hole.

Benefit: The position of the slot should measure at center in both the direction with respect to the thread hole. For ease of assembly hole should be collinear and at the center of a slot.

Die-Casting Rule

1. Minimum Draft Angle:

Draft angle design is an important factor when designing die casting. Parts may have a greater tendency to shrink onto a core side, this creates higher contact pressure on the core surface and increases friction between the core and the part, thus making ejection of the part from the mold difficult.

If the draft angle is small, even the slightest depression in the drafted surface of die will prevent ejection which will cause drag marks in the surface of the casting.

Benefit: Draft angles should be designed properly to assist in part ejection. Draft angles should be used on interior or exterior walls of the part along the pulling direction. This also reduces cycle time and improves productivity.

2. Mold Wall Thickness:

Mold wall thickness gets affected due to spacing between various features in the die-casting model. If features like ribs, bosses are placed close to each other or the walls of the parts, thin areas are created which can be hard to cool and can affect quality. If the mold wall is too thin, it is also difficult to manufacture and can also result in a lower life for the mold due to problems like hot blade creation and differential cooling.

Mold Wall Thickness

Fig 3: Mold Wall Thickness

Benefit: Minimum allowable mold wall thickness needs to be decided based on process and material considerations. However, it is normal to have clearances of one mm between features of an injection molded plastic part thus allowing a mold wall of that dimension.

3. Recommended Cored Holes:

Holes in die-casting part is mostly preferred cored holes. If minimum hole sizes (D) based on material is below a certain defined value, then it can’t be easily cored. Hole must be drilled rather than using coring as an operation.

Benefit: Larger holes can be cored in die casting as appreciable amount of metal can be saved. Also machining operation can be speeded up or even eliminated. Avoid minute cores which can be easily bent or broken and require frequent replacement.

Sheet Metal Rules

Minimum Distance Between Perforated Cutouts:

Perforated cutouts which are too close to each other can cause problems during fabrication. In case of stamped cutouts, the part of the die block that supports the stamping between these features will have a thin section that can crack or break in production. 

Benefit: Distortion can also occur due to insufficient space for clamping because of the crowding of features. Such cases can be identified easily by DFMPro.

Also to cater needs of 3D printing, For bringing ideas into reality to cater needs of much spoken 3D printing process these days, some of guidelines for additive manufacturing has been made available here.

Moreover, this release of DFMPro delivers noticeable enhancements. Watch out this space for more updates!

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