Unveiling the Technological Craftsmanship of Part Structures

Tools of CNC Machining Parts

Common Casting Structures


To facilitate the removal of the cast from the mold and reduce resistance, a certain degree of taper is added in the design along the molding direction. This taper helps the cast to be easily removed from the mold without getting stuck or damaged. Typically, the taper is set around 3 degrees, approximately 1:20 in ratio. For small parts, this taper can be omitted from the drawing, but for large parts, it must be clearly marked.

online cnc machining service


To prevent damage to the sand mold during casting and avoid shrinkage cavities and cracks during cooling, the edges of the cast are designed as fillets. This design prevents sharp corners that can lead to cracks, thus improving the strength and longevity of the cast.

Wall Thickness Equality

The design should aim for uniform wall thickness to avoid defects such as shrinkage cavities and cracks caused by uneven cooling rates. Gradual changes in wall thickness are crucial to prevent sudden changes that can lead to stress concentration and cracks.

Least Wall Thickness

The wall thickness of the cast should not be too thin to ensure the mold cavity is fully filled, thus preventing defective products. Therefore, the minimum wall thickness must be specified in the design to ensure the integrity and quality of the cast.

Common Machining Structures

Cylindrical Projection or Recessed Surface

To ensure stable contact between the machined parts, reduce the machined surface, and lower costs, projections and recesses are often added to the design. These structures not only reduce machining time and difficulty but also enhance the stability of the parts.

Chamfer or Radius

To avoid stress concentration and facilitate installation and safety, small chamfers or radii are added at the ends of rods or at the transitions of shafts. This design prevents sharp edges from causing injury and avoids breakage due to stress concentration.


To facilitate tool withdrawal and avoid incomplete machining surfaces, undercuts are designed at shafts or holes. This sudden change in diameter significantly improves machining efficiency and reduces the defect rate.

Drill Hole

For easy positioning and to prevent drill bit damage, the surface to be drilled must be perpendicular or greater than 60 degrees to the axis of the hole. Common drill hole structures include blind holes, tapered holes, countersunk holes, and spot faces.

Common Sheet Pressing Structures


To avoid stress concentration at sharp corners and prevent fractures, the external and internal corners of the sheet pressing parts are designed as small radii. This design significantly improves the strength and longevity of the sheet pressing parts.

Least Bend Radius

To prevent the sheet material from breaking during bending, the minimum bend radius must be restricted. A small bend radius can lead to cracks or fractures during the bending process, affecting product quality.

Enchasing Structures

Enchasing Design

To ensure a secure connection and improve the adhesion of the bonding surfaces, projections and grooves are designed on the surface of the enchasing parts. To avoid stress concentration at the sharp corners of the enchasing parts, fillets are added at the ends and grooves. This design improves the strength and durability of the enchasing parts.

Example Data Table

To better understand the technological craftsmanship of part structures, the following data table compares the effects of different designs:

ItemDesign RequirementsAdvantagesDisadvantages
Taper3 degreesFacilitates mold removal, reduces resistanceMay increase design complexity
FilletR3~5Prevents sand mold damage, reduces shrinkage and cracksIncreases machining time and cost
Wall Thickness EqualityUniform wall thicknessAvoids defects due to uneven coolingIncreases design difficulty
Least Wall ThicknessSpecified minimum thicknessEnsures mold cavity is fully filled, reduces defectsRequires precise calculation and control
Projection and RecessUneven heightEnhances part stability, reduces machining time and costUneven height increases machining difficulty and time
Chamfer and RadiusSmall chamfer or radiusAvoids stress concentration, facilitates installation and safetyIncreases design and machining complexity
UndercutGroove designImproves machining efficiency, reduces defectsRequires precise tools and techniques
Drill HolePerpendicular or >60 degreesPrevents drill bit damage, ensures hole accuracyRequires precise positioning and operation
RadiusSharp corners to small radiiPrevents fractures, improves strengthIncreases design and machining time
Bend RadiusRestricted minimum radiusPrevents cracks or fractures during bendingRequires strict control of bend radius
Enchasing DesignProjections and groovesImproves strength and durability of enchasing partsIncreases design and machining complexity

Through the above table, it is easier to understand how different designs impact the technological craftsmanship of part structures, helping us make better decisions during the design and machining process. The craftsmanship of part structures not only affects the quality and performance of the product but also directly relates to production costs and efficiency. Therefore, during the design and machining process, we need to consider various factors comprehensively to ensure the optimal craftsmanship of the parts.

Learn more:
Want.Net Technical Team

Want.Net Technical Team

The Want.Net Technical Team has diverse members with extensive education and training in CNC machining. They prioritize precision, efficiency, and innovation to provide high-quality manufacturing solutions globally.

Push Your Order into Production Today!

Table of Contents


You’re one step from the  factory-direct price of part manufacturing services.