Custom Cold-Process Silicone Soap Mold | Dutch 2024 Project
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Product |
Cold-Process Silicone Soap Mold |
|---|---|
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Order Quantity |
Initial Order: 24,000 pcs |
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Material |
Food-Grade Solid Silicone |
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Key Specs |
Hardness: Shore A25-32 |
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Certification |
LFGB, FDA |
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Lead Time |
DFM Evaluation: 24 hrs |
Project details
A Dutch craft mold brand needed a series of silicone molds for handmade cold-process soap, with each design carrying a distinct decorative pattern and brand identity. The mold cavities covered multiple styles, from mythological dragons to Western serpent motifs, allowing end users to produce soap and other handmade items with detailed surface patterns.
In use, the customer selects the required soap shape, pours the soap mixture into the mold, and removes the finished piece after it cools and hardens. Standard soap molds available on the market generally offered fixed material hardness and limited structural customization. These products did not provide the demolding feel required by the client and could not incorporate the client’s customized logo and cavity patterns.
Drawing on 19 years of custom silicone product experience, Z.S.R Group handled the complete customization process, including the irregular mold geometry, embossed branding on the bottom, and the client’s printed logo. The engineering team converted the supplied artwork into manufacturable drawings and carried out a DFM review of the mold structure.
The main changes included adding draft angles and an overflow collector, adjusting the wall-thickness distribution, and replacing sharp internal corners with radiused transitions.
Delivery data
Engineering DFM Assessment
Draft Angle and Demolding Geometry
To reduce resistance during demolding, Z.S.R Group added a 1.5° draft angle to the mold sidewalls. Sharp internal corners in the cavity were replaced with rounded transitions, with a specified corner radius of ≥0.8 mm.
The original right-angle cavity geometry made venting more difficult during both silicone molding and soap preparation. Air could remain trapped around sharp internal features, increasing the risk of incomplete edge formation and cracking in the finished piece.
The original structure also lacked sufficient draft for releasing hardened soap from the cavity. The 1.5° draft angle, combined with radiused internal corners, reduces mechanical interference between the solidified soap and the cavity walls during removal and improves the probability of complete demolding.
Overflow Collection
A ring-shaped overflow collector was incorporated around the upper perimeter of the mold.
During manual soap preparation, the amount of soap mixture poured into an individual cavity can vary. Excess material from an overfilled cavity would otherwise flow directly onto the surrounding mold surface and require additional cleaning.
The perimeter collector provides a defined area for receiving excess soap mixture during pouring, containing overflow around the cavity rather than allowing it to spread across the mold surface.
Wall-Thickness Distribution
The cavity sidewalls were specified at 2.5 mm, while the mold bottom was increased to 3 mm.
This thickness distribution was selected around the mechanical requirements of repeated demolding. Silicone soap molds are repeatedly stretched, inverted, and compressed when finished pieces are removed. The bottom section experiences higher deformation loads during this process and therefore requires greater section thickness.
The 3 mm bottom provides additional material in the higher-load region, while the 2.5 mm sidewalls retain greater flexibility around the cavity. This balance gives the user a softer wall section for peeling the mold away from the finished soap without reducing the structural support provided by the base.
Mold Making, Sample Production & Quality Verification
Mold Machining
Z.S.R Group operates 6 advanced CNC machining centers and 4 EDM machining centers for silicone mold manufacturing.
For this project, the mold core was produced using copper etching technology to reproduce the detailed patterns and surface textures specified by the client. Stainless steel top and bottom molds were then used as part of the tooling structure.
Because of the customized cavity artwork and tooling requirements, the total mold production time exceeded 50 days.
Solid Silicone Molding
Production is supported by 48 solid-state molding machines, with capacity to mold 24,000 silicone molds within 20 days.
The molding process was configured around the irregular cavity geometry, detailed etched surfaces, and specified 2.5 mm sidewall / 3 mm bottom thickness distribution.
Secondary Vulcanization
After molding, the silicone parts undergo secondary vulcanization at 180°C for 2 hours.
The parts are then thoroughly cooled in a ventilated environment. This post-curing process is used to reduce residual volatile substances in the silicone and minimize residual odor, supporting the material and finish requirements specified by the client.
Quality Inspection:
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Test |
Condition |
Acceptance Criteria |
Result |
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100% Appearance Inspection |
Inspect the surface for defects, deformation, damage, and burrs |
No defects, deformation, damage, or burrs |
Pass |
|
Demolding Durability Test |
Demolding ≥ 3,000 cycles |
No cracking or deformation of the mold; no wear on the pattern |
Pass |
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High- and Low-Temperature Test |
Alternate between high- and low-temperature environments at -40°C and 220°C |
No damage, aging, or deformation |
Pass |
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Third-Party Laboratory Testing |
Testing conducted by an independent laboratory |
Complies with FDA and LFGB food-grade standards |
Pass |
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Simulated Actual-Use Condition Test |
Simulate daily filling, demolding, and cleaning conditions |
Stable mold structure with no cracking or deformation |
Pass |
Related Silicone Mold Product
Customer reviews & feedback
The initial trial production order was 24,000 pieces. After receiving the order, the customer reported that the soap molds had a hardness of around 25 degrees, which was very beneficial for demolding soaps and other handicrafts. We were very satisfied with this batch of soap molds. The customer subsequently placed repeat orders.
From 2024 to 2026, we continued to develop soap molds with different internal patterns, increasing the number of designs from the original 48 to 160. We also added 4-cavity soap molds and opened different types of steel molds for soap mold production. Repeat orders totaling 9,000 pieces were placed in 2023, 2024, 2025, and 2026. On September 2, 2026, this Dutch customer just arranged production for a new order of 4-cavity soap molds.
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