Soap Box Injection Mold Spacer Processing Procedure
Comprehensive manufacturing guidelines for precision components in custom plastic molding applications
Part Overview
As shown in Figure 2-15, the spacer for the soap box injection mold is a relatively simple component made from 45 steel with a hardness requirement of 28HRC. This component plays a crucial role in custom plastic molding operations, ensuring proper mold alignment and functionality.
The upper and lower surfaces have parallelism requirements and a surface roughness of Ra 1.6μm. Each of these surfaces features two 30mm×30mm ejection slots with a depth of 5mm. The lower surface contains two M10 threaded holes with a depth of 20mm.
All other holes in the component are through holes with no tolerance requirements for either diameter or positional dimensions. This simplicity makes it well-suited for efficient production in custom plastic molding environments.
Figure 2-15: Soap box injection mold spacer technical drawing with key dimensions
Key Dimensions and Specifications
Main Dimensions
The overall dimensions of the spacer are 350mm × 58mm × 90mm, with the height dimension (90±0.05)mm being critical for proper functioning in custom plastic molding applications.
Surface Finish
Upper and lower surfaces require a surface roughness of Ra 1.6μm to ensure proper contact and parallelism in the mold assembly, a standard requirement in precision custom plastic molding.
Material Specifications
Constructed from 45 steel with a heat treatment hardness of 28HRC, providing adequate strength and durability for custom plastic molding operations.
Hole Specifications
Features two M10 threaded holes (depth 20mm) and multiple through holes including 3×φ16mm and 2×φ40mm holes, all strategically positioned for mold assembly in custom plastic molding applications.
1. Part Process Analysis
This component is positioned above the moving mold base plate, on both sides of the ejection plate. Its primary function is to support the moving mold backing plate while providing sufficient ejection distance for the ejection plate. In custom plastic molding operations, the spacer does not make relative contact with other components during mold operation.
Analysis of the drawings reveals that only the height dimension has precision requirements, while other dimensions utilize free tolerances which are sufficient for their intended purpose in custom plastic molding. Geometric tolerances and surface roughness requirements are only specified for the upper and lower surfaces.
Spacer position within the mold assembly for custom plastic molding applications
Since this is not a molding component and does not make relative contact with other parts during operation, the use of 45 steel with a heat treatment hardness of 28HRC is appropriate for custom plastic molding requirements.
Structurally, the component is relatively simple and does not require high hardness. Machining of all surfaces, grooves, and holes can be achieved conveniently, resulting in good structural processability. The main machining operations involve flat surfaces and holes, with the key requirement being to ensure the height dimension of (90±0.05)mm for the upper and lower surfaces, critical for proper functioning in custom plastic molding.
In custom plastic molding, these dimensional accuracies ensure that the mold operates smoothly, preventing issues like flash formation or improper part release that could compromise product quality.
2. Blank Selection
The component has a hexahedral shape with maximum outline dimensions of 350mm × 58mm × 90mm, constructed from 45 steel. Two types of blanks can be considered: steel plate sections and forgings, each with implications for custom plastic molding production efficiency and cost.
Since the component only bears pressure from the core plate and has a simple stress state during custom plastic molding operations, cut-to-size steel plate sections are sufficient to meet mechanical performance requirements. Forgings would result in longer production cycles and higher costs without significant benefits for this application.
Therefore, material can be cut from 100mm thick steel plate into 65mm × 360mm sections, or alternatively from 65mm thick steel plate into 100mm × 360mm sections. The choice depends on material availability and production efficiency considerations in custom plastic molding facilities.
From a production type perspective, this spacer is a component in standard mold bases. For manufacturers of standard mold bases supplying the custom plastic molding industry, this component is produced in batches and can use die forging or steel plate cutting for blank preparation.
For general mold companies that do not use standard mold bases in their custom plastic molding operations, this component is produced as a single piece, and steel plate cutting is appropriate. Most modern mold companies in the custom plastic molding sector utilize standard mold bases, eliminating the need for separate processing of this component and thus the blank selection decision.
Blank Selection Criteria
Key factors in choosing the optimal blank for custom plastic molding components
- Mechanical performance requirements for custom plastic molding applications
- Production cycle considerations and lead time requirements
- Cost-effectiveness for the specific production volume
- Material utilization and waste minimization
- Compatibility with existing manufacturing processes in custom plastic molding facilities
- Availability of raw materials and standard sizes
3. Selection of Locating Datums
Due to the hexahedral shape of the component, the mutual datum principle can be used to select machining datums for processing the three pairs of parallel surfaces during milling operations. This approach is commonly employed in custom plastic molding component manufacturing to ensure dimensional accuracy.
Datum selection for hexahedral components in custom plastic molding
Datum Selection Principles
The two surfaces with Ra 1.6μm surface roughness require higher precision and can also be ground using the mutual datum principle, a standard technique in custom plastic molding component production.
It's important to note that there are no perpendicularity requirements between the surrounding surfaces or between the surrounding surfaces and the upper/lower surfaces. Therefore, using the mutual datum principle is sufficient for meeting functional requirements in custom plastic molding applications.
If perpendicularity requirements existed between the surrounding surfaces and the upper/lower surfaces, a unified datum principle would be necessary. This would involve machining the two surfaces with perpendicularity requirements in one setup, then using these surfaces as datums for machining the remaining surfaces to ensure the required part geometry in custom plastic molding.
Best Practice in Datum Selection
In custom plastic molding component manufacturing, datum selection directly impacts dimensional accuracy and production efficiency. The mutual datum approach offers flexibility for components without complex geometric tolerances, reducing setup times while maintaining required precision. For components with stricter geometric relationships, unified datums ensure consistent results across production runs, critical for maintaining interchangeability in custom plastic molding applications.
4. Process Route Development
The main body of the component is hexahedral, allowing for a streamlined manufacturing process that balances precision and efficiency in custom plastic molding component production.
The manufacturing process begins with the prepared blank, proceeding through rough milling, quenching and tempering heat treatment, and finish milling of all surfaces. A grinding allowance of 0.3-0.5mm is left on both the upper and lower surfaces, while all other surfaces are milled to final dimensions. This approach is typical in custom plastic molding component production to balance processing efficiency with final precision requirements.
The small ejection steps at the four corners of the upper and lower surfaces are machined during this phase. The height dimension and parallelism requirements of the upper and lower surfaces are critical and are ensured by surface grinding both spacers simultaneously on a surface grinder, achieving the required dimensions and surface roughness for the hexahedral shape of the spacer in custom plastic molding applications.
Material Cutting
Preparation of initial material stock to approximate dimensions
Surface Milling
Rough and finish milling of all surfaces with appropriate allowances
Surface Grinding
Precision grinding of upper and lower surfaces to final dimensions
Layout Work
Marking hole positions and contours for subsequent machining
Drilling & Reaming
Creating all through holes to specified diameters
Thread Tapping
Creating threads in specified holes for assembly purposes
Inspection
Verification of all dimensions and specifications before use
Hole dimensional accuracy requirements are not high, and for single-piece and small-batch production typical in custom plastic molding, layout positioning is sufficient. Holes are then drilled and reamed as needed. Finally, the钳工 (fitter) drills the fixing screw counterbores and taps the threads, or alternatively, after finish milling, all holes can be directly machined on the milling machine to complete the spacer for the standard mold base.
Overall, machining of this component is primarily performed on milling machines, following the principle of process concentration. In custom plastic molding component production, this approach minimizes setup changes and improves efficiency.
Since the surrounding surfaces and all holes are through holes, the economic accuracy of rough machining is sufficient for their functional requirements in custom plastic molding applications, eliminating the need for finishing operations. Only the upper and lower surfaces have precision requirements, so a single grinding operation is scheduled as the finishing process for these surfaces.
The final determined machining process route for the spacer in custom plastic molding production is: Material cutting → Surface milling → Surface grinding → Layout work → Drilling and reaming holes → Thread tapping → Inspection.
5. Process Content Design
Operation 1: Material Cutting
Cut material to dimensions of 100mm × 65mm × 360mm. This initial stock provides sufficient material for subsequent machining operations while minimizing waste, an important consideration in cost-effective custom plastic molding component production.
Operation 2: Milling
Mill all six surfaces, leaving 0.15mm allowance on both ends of the 90mm dimension. All other dimensions are machined to drawing specifications. Mill the ejection platforms to final size, ensuring proper functionality in custom plastic molding operations.
Equipment: Universal vertical milling machine X52K
Measuring tools: 0.02mm × 500mm vernier caliper for dimensional verification
Operation 3: Grinding
Grind to the 90mm dimension, achieving the specified requirements on both ends. This operation ensures the critical height dimension and surface finish required for proper functioning in custom plastic molding applications.
The grinding process establishes the final parallelism between the upper and lower surfaces, which is essential for uniform pressure distribution during the custom plastic molding process.
Equipment: Surface grinder M7130
Operation 4: Fitting Work
Layout all hole positions and contours, marking with center punches. This step ensures accurate positioning of all features critical to the component's function in custom plastic molding assemblies.
Precise layout work is essential for ensuring that all holes align properly with corresponding components in the mold assembly, preventing issues during custom plastic molding production.
Operation 5: Drilling
Following the layout lines, perform the following drilling operations critical for the component's role in custom plastic molding assemblies:
Threaded Holes
- Pre-drill 2×M10 threaded holes with φ6mm twist drill
- Finish drill with φ7.8mm twist drill to final size for threading
φ16mm Holes
Drill 3×φ16mm holes using appropriate drill bits, ensuring proper size for their intended function in custom plastic molding applications.
φ40mm Holes
Drill 2×φ40mm holes, creating the necessary clearance for components in the custom plastic molding assembly.
Equipment: Z3025 radial drilling machine, equipped with appropriate drill bits for each hole size
Operation 6: Thread Tapping & Inspection
Thread Tapping
Tap the 2×M10 holes to create the required threads for fasteners in the custom plastic molding assembly. Proper thread formation is critical for secure assembly and maintenance of mold alignment during repeated cycles.
Tools: M10 tap set with appropriate tap wrench, cutting fluid for improved thread quality
Inspection
Perform comprehensive inspection of all dimensions, surface finishes, and features to ensure compliance with drawing specifications for custom plastic molding applications.
Key inspection points include:
- Height dimension (90±0.05)mm verification
- Surface roughness of upper and lower surfaces
- Parallelism between upper and lower surfaces
- Hole positions and diameters
- Thread quality and dimensions
Quality Control in Custom Plastic Molding Component Production
Maintaining strict quality control throughout the manufacturing process is essential for producing reliable components for custom plastic molding applications. For the soap box injection mold spacer, several key quality checkpoints ensure the final product meets all requirements.
After the grinding operation, critical dimensions including the height (90±0.05)mm must be verified using precision measuring instruments. Surface roughness testing should confirm that the upper and lower surfaces meet the Ra 1.6μm requirement, which is vital for proper mold function in custom plastic molding.
Parallelism between the upper and lower surfaces is checked using a surface plate and dial indicator, ensuring that the spacer will properly distribute pressure during custom plastic molding operations. This prevents uneven wear and potential mold damage.
Final inspection before component acceptance includes a comprehensive check of all dimensions, hole positions, thread quality, and surface finishes. Only components meeting all specifications are approved for use in custom plastic molding applications, ensuring mold reliability and product quality.
Precision measurement of mold components ensures quality in custom plastic molding production
This comprehensive processing procedure ensures that the soap box injection mold spacer meets all required specifications for reliable performance in custom plastic molding applications. Following these detailed steps guarantees consistent quality, proper functionality, and long service life in production environments.
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