Custom Silicone Straw Cup | Polish 2023 Project
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Product |
Children’s Double-Ear Silicone Straw Training Cup |
|---|---|
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Order Quantity |
Initial Order: 55,000 pcs |
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Material |
Food-Grade Liquid Silicone |
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Key Specs |
Hardness: Shore A45 Temperature Resistance: -40°C to 230°C |
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Certification |
FDA, LFGB, REACH |
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Lead Time |
DFM Evaluation: 24 hrs |
Project details
A Polish mother and baby brand specializing in infant food and sippy cups wanted to develop a silicone sippy cup for sale exclusively in offline mother and baby stores. The client’s existing samples had issues with leakage at the rim and straw, and the handle turned white during use.
Introduced by a friend, the client found Z.S.R, a company with many years of experience in silicone product manufacturing and problem-solving. The engineering team optimized the sample’s DFM structure based on the client’s pain points and needs, resolving the leakage issue.
Based on the DFM results, the project moved into mold making and sample production, followed by quality verification of the first batch before mass production.
Delivery data
Engineering DFM Assessment
Optimized Sealing Structure Between Lid and Body
Z.S.R recommended adding a 1.0 mm high, 0.8 mm thick sealing lip to the inner ring of the lid, optimizing the lip compression based on the properties of 45 Shore A LSR material, and adding a 0.5 mm positioning boss at the top of the cup rim.
In the original design, the radial interference seal between the lid and the cylindrical surface of the cup body was significantly affected by temperature. Pouring warm water into the cup would cause leakage due to changes in the fit clearance. The lip seal, however, is independent of radial dimensional fluctuations, and the positioning boss further ensures consistent lip alignment, improving seal reliability.
Double Sealing at the Straw Perforation
A 0.6 mm high reverse sealing ring was added at the straw perforation in the lid, the bottom of the straw was flared and inverted onto the inside of the lid, and the tip of the straw was rounded with a 1.2 mm radius.
The straw passes directly through the round hole in the lid, and any deviation in the straw’s outer diameter worsens the seal. The rounded corner at the bite point, the reverse sealing ring, and the flared edge improve the sucking experience for children and prevent the straw from slipping off.
Optimized Handle Base Structure
The radius at the handle base was increased from 0.5 mm to 1.3 mm, a 0.6 mm reinforcing rib was added inside, and a smooth, gradual transition in wall thickness was created at the connection between the handle and the body.
The original design had an excessively small radius at the base of the handle, resulting in a sudden change in wall thickness. When children grip and pull the handle, stress tends to concentrate at the corner, leading to whitening and breakage over time. A gradual wall thickness, reinforcing ribs, and a larger radius disperse stress and extend the handle’s lifespan.
Mold Making, Sample Production & Quality Verification
Mold Processing
Z.S.R Group is equipped with 10 advanced CNC machining centers and 4 EDM machines for liquid silicone cup molds. The cup body, lid, and straw are developed using three separate molds. The mold core is mirror-polished to Ra0.4 μm, ensuring a smooth, burr-free product surface.
Silicone Molding
Production is supported by 48 solid molding machines, 12 liquid molding machines, and 13 injection molding machines using liquid silicone injection molding technology, enabling the rapid molding of 25,000 silicone straw cups within 20 days. Over 10 printing and spraying production lines also allow for printing logos or patterns on the silicone cups.
Secondary Vulcanization
After molding, the silicone straw cups undergo secondary vulcanization at 200°C for 2 hours.
The secondary curing process removes small-molecule volatiles from the silicone, reducing product odor and meeting the safety requirements for infant food contact.
Quality Inspection
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Test |
Condition |
Acceptance Criteria |
Result |
|---|---|---|---|
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Visual Inspection |
100% inspection of cup body, lid, and straw surfaces |
No bubbles, scratches, dirt, flash, or burrs |
Pass |
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Sealing & Leak-Proof Test |
37°C warm water, inverted and shaken for 30 seconds |
No leakage at the lid or straw insertion holes |
Pass |
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Handle Fatigue Test |
Double-ear handles repeatedly pulled 5,000 times |
No whitening, cracks, or breakage |
Pass |
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Straw Pull Test |
Straw pulled vertically outward |
Pull force ≥ 30 N, straw must not detach |
Pass |
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Dimensional Accuracy Inspection |
Caliper measurement of key fitting dimensions |
Key dimensions controlled within ±0.08 mm |
Pass |
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Food Contact Test |
Laboratory chemical migration testing |
Meets relevant FDA and LFGB requirements |
Pass |
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Hazardous Substances Test |
REACH SVHC testing |
Meets REACH SVHC limit requirements |
Pass |
The production samples passed the specified visual, sealing and leak-proof, handle fatigue, straw pull, dimensional, food contact, and hazardous substances inspections. In particular, no leakage was observed at the lid or straw insertion holes in the 37°C warm water inverted shake test.
Related Product
Customer reviews & feedback
“The straw cups your factory produced for me are extremely durable. Customers unanimously agree that they are the most durable straw cups they have ever used. Many reviews express their strong impression of the product.”
Custom Silicone Straw Cup
OEM & ODM solutions for brands, retailers, wholesalers, and Ecommerce sellers. Food-grade liquid silicone straw cups with FDA/LFGB/REACH compliance.
Other Project
For industrial-scale production, ZSR Group also operates a dedicated silicone compression molding service for custom silicone parts.
