Plastic Stool Mould Maker: Stackable, Step, Rattan & Foldable Stool Tooling
We design and manufacture high-speed injection moulds for stackable bar/dining stools, bathroom step stools, rattan-pattern stools, and 5-piece foldable stools. Built in P20H / 718H / DIN 1.2738 steel with 4-way tapered anti-shift interlocks and air-assisted stripper ejection — achieving 18–28s cycle times on 280T–650T presses.
- 4-Way Tapered Locks (Zero Core Shift)
- 18–28s Fast-Cycle BeCu Cooling
- 1-Cavity, 2-Cavity & Foldable Stool Sets
- TPE Anti-Slip Foot & IML Ready
Why Deep-Draw Stool Moulds Suffer from Cracking & Sticking
A tall stackable stool (450–500 mm height) has a deep, narrow tapered core with minimal draft angle (often 1°–1.5°). Three tooling mistakes ruin stool production:
Deep-Core Deflection (Uneven Leg Walls)
During high-speed injection, the long cantilevered core can bend 0.4 mm to one side — leaving two stool legs paper-thin (1.6 mm) and two legs overly thick (2.8 mm), causing sudden leg buckling under load.
Vacuum Sticking & Top-Seat White Marks
Polypropylene shrinks tightly onto the deep male core. Without air-poppet vacuum breakers and bottom rim stripping, ejector pins punch white stress marks right through the top sitting surface.
Side-Slider Flash on Rattan Weave Stools
Rattan and hollow-carved stools require 4-way split sliders. Poor slider wedge preload or soft shut-off steel creates unsightly vertical seam flash down all four corners of the stool.
Plastic Stool Mould Specifications: Standard vs. High-Output
| Tooling Parameter | Standard Household Stool Mould | High-Speed / Multi-Cavity Stool Mould |
|---|---|---|
| Cavity Configuration | 1 Cavity (Tall Bar/Dining Stool) | 2 Cavities (Low Step/Bath Stool) or Complete Foldable Stool Set |
| Cavity & Core Steel | P20H / 718H (Pre-hardened HRC 30–34) | DIN 1.2738 / H13 (1.2344) with Nitrided Slider Locks |
| Core-Shift Alignment | 4-Sided Tapered Parting Interlocks | Heavy Zero-Clearance Tapered Blocks + Top Centering Ring |
| Cooling System | Spiral Core Baffle + Independent Slider Circuits | Beryllium-Copper (BeCu) Core Cap + Conformal Cooling |
| Runner & Gate | 1-Drop Open Hot Runner or Cold Sprue | Valve-Gate Hot Runner (Clean Under-Seat or Hand-Hole Gate) |
| Ejection Mechanism | Bottom Leg-Tip Ejector Blocks + Air Poppet | Synchronized Hydraulic Stripper Ring + Dual Air Poppets |
| Press Tonnage | 280T – 450T | 450T – 750T |
| Target Cycle Time | 26 – 35 seconds | 18 – 24 seconds |
| Guaranteed Mould Life | 500,000 shots | 800,000 – 1,000,000+ shots |
Stool Moulds We Design & Build
Stackable Dining & Rattan Stools
450 mm high round and square stackable stools with 4-slider rattan textures, wood-grain finishes, or smooth glossy surfaces.
Foldable Step Stools (1-Mold or 2-Mold Sets)
popular collapsible carry-handle step stools engineered with precision hinge knuckles that snap together smoothly and hold 150 kg static load.
Bathroom, Toilet & Anti-Slip Kids Stools
1- or 2-cavity step stools and squatting toilet stools, supporting 2K TPE overmolded anti-slip foot pads and In-Mold Labeling (IML) cartoon graphics.
Preventing Core Shift & Top-Surface Ejector Marks
1. 4-Way Tapered Interlocks & X-Rib Stiffening
To keep wall thickness within ±0.08 mm across a 480 mm tall stool, we machine heavy 15° tapered interlocks on all four sides of the mold base and optimize the under-seat X-shaped gusset ribs (root thickness ≤ 0.6T) so the seat supports 150+ kg without top sink marks.
2. Invisible Rim Ejection + Air-Poppet Release
We never place ejector pins against the thin top sitting panel. Instead, a timed compressed-air poppet valve breaks the vacuum at the top of the core while concealed stripper blocks push evenly on the bottom leg rims and internal rib intersections.
Cycle-Time ROI & 40-Day Delivery
By capping the top of the deep stool core with high-conductivity Beryllium-Copper (BeCu), we drop cycle time from 32 seconds down to 22 seconds — increasing output on a 380T press from 2,700 stools/day to 3,920 stools/day (+1,220 extra stools every day). Check your exact piece cost with our unit cost breakdown tool.
Day 1–2: 24h Quote & Free DFM
Share your stool sample or 3D file. We check stacking pitch, rib-to-wall ratios, and hinge clearances in a free DFM report.
Day 3–30: CNC Machining, Slider Spotting & Texturing
Precision 5-axis CNC, deep-hole cooling drilling, 4-slider shut-off spotting, and chemical/laser grain etching.
Day 31–40: T1 Trial, Load Testing & Shipment
We test cycle speed, 150 kg center-load deflection, and 15-high stacking stability before air-shipping T1 samples.
Sourcing a Stackable, Rattan, or Foldable Stool Mould?
Send your stool dimensions, weight, or sample photo. Get a complete DFM review, press tonnage recommendation, and factory-direct quote in 24 hours.
Plastic Stool Mould FAQ
How much does a plastic stool mould cost in China?
A single-cavity simple stackable or bathroom step stool mould in P20H/718H steel typically costs between USD 8,500 and USD 16,000. A 4-slider rattan-weave tall stool mould, a 2-cavity low stool mould, or a complete multi-part foldable step stool mould set ranges from USD 16,000 to USD 32,000+.
How many moulds are needed for a foldable plastic step stool?
A standard 5-piece foldable step stool consists of 1 top platform, 2 long hinged side panels, and 2 short hinged side panels. Depending on your press size and volume, we can build either a single family mould (all 5 parts in 1 shot on a 450T–550T press) or a 2-mould high-output set (1 mould for the top + 1 mould for the 4 side panels).
How do you prevent white stress marks on the top of a moulded stool?
White marks happen when ejector pins push against a still-hot top panel or when vacuum locks the part onto the deep core. We use a compressed-air poppet valve on the top core face to release vacuum instantly and push exclusively on the bottom leg rims and reinforced rib roots.
Can you add TPE anti-slip rubber feet to a step stool or toilet stool?
Yes. We either build a small multi-cavity TPE foot-pad mould that snaps into undercuts on the stool legs, or we engineer a 2-shot (overmolding) tool where TPE is injected directly onto the PP stool feet.
