PP Hollow Construction Formwork Extrusion Line— CX Series Twin-Screw Co-Extrusion Line for Reusable Plastic Formwork Panels

Product Overview

The CX Series PP Hollow Construction Formwork Extrusion Equipment is a fully automated twin-screw co-extrusion production line engineered by Chenxing Machinery for manufacturing high-performance PP (polypropylene) hollow plastic formwork panels. Designed to replace traditional steel, wood, and bamboo formwork in concrete construction, this line produces lightweight yet structurally robust hollow-core sheets with a honeycomb/tubular internal architecture that delivers exceptional stiffness-to-weight ratio and reusability.

Available in two configurations — CX120/75 (450–500 kg/h) and CX150/80 (550–600 kg/h) — the CX series accommodates standard construction formwork dimensions of 915×1220 mm and 915×1830 mm (dual-extruder wide panel), with thicknesses adjustable from 10 mm to 18 mm. The twin-screw co-extrusion system enables three-layer composite panel construction: dense, smooth top and bottom surface layers encasing a hollow-core middle layer that reduces weight without sacrificing load-bearing performance.

As global construction shifts toward sustainable, reusable formwork solutions that eliminate timber waste and reduce steel consumption, the CX Series positions fabricators to capture growing demand in emerging and developed markets alike. The line integrates seamlessly with upstream material preparation systems — including high-speed mixer for compound blending and plastic crusher for edge-trim recycling — forming a closed-loop production ecosystem.

Complete Production Line Layout

The CX Series is a turnkey line comprising nine integrated subsystems, each purpose-built for continuous, unattended operation:

Twin-Screw Co-Extrusion System — SJ Series Dual Extruder with Hollow-Core Die

The heart of the CX Series is its twin-screw co-extrusion system, comprising two independently controlled SJ-series extruders that feed a shared hollow-core die head. The main extruder (SJ75/30 on CX120/75, SJ150/35 on CX150/80) processes the bulk core-layer PP modified compound, while the auxiliary extruder (SJ30/35 on CX120/75, SJ80/30 on CX150/80) delivers the surface-layer material. This configuration produces panels with dense, smooth outer surfaces and a lightweight hollow interior — a structure that maximizes flexural rigidity while minimizing material usage.

Bimetallic barrels and nitride-hardened screws ensure long service life even with abrasive PP modified compounds containing mineral fillers and reinforcing agents. The die head incorporates a proprietary flow-channel geometry that evenly distributes melt across the full panel width, eliminating thickness variation and core-cell collapse.

Calibration, Haul-Off & Automatic Cutting/Stacking

Post-extrusion, the hot panel enters a multi-stage calibration and cooling section. Precision calibration plates establish final thickness (±0.2 mm tolerance) while water-circulation cooling jackets rapidly lower the panel temperature below the PP crystallization point, locking in dimensional stability. A downstream haul-off unit — functionally similar to our caterpillar haul-off machine technology adapted for flat sheet — maintains constant pulling speed via closed-loop servo control.

The integrated dust-free cutting system — derived from our proven pipe-cutting platform — executes clean, square cuts at user-defined lengths without generating airborne particulate. Finished panels are then automatically stacked by a pneumatic handling system, ready for palletizing and shipment.

Technical Specifications

Key Features

1. Long Service Life & High Reuse Cycles

PP hollow formwork panels produced on the CX series achieve significantly more reuse cycles than plywood or bamboo formwork — often 50+ pours per panel face. The modified PP compound resists edge crushing, screw pull-out, and moisture-induced delamination, reducing per-pour formwork cost to a fraction of traditional materials. This durability directly translates to lower total cost of ownership for construction contractors.

2. No Secondary Finishing Required

The co-extruded surface layers produce panels with a smooth, defect-free concrete-contact face straight off the line. After demolding, concrete surfaces require no grinding, patching, or painting — a stark contrast to timber formwork that leaves grain impressions and requires extensive post-pour finishing labor.

3. Effortless Demolding

PP's inherently low surface energy means cement paste does not bond to the panel surface. Workers can strip formwork quickly without chemical release agents in most applications, accelerating pour-to-pour cycle times and reducing labor hours on site.

4. Superior Dimensional Stability — No Warping or Delamination

Unlike plywood formwork that swells, warps, and delaminates after water exposure, PP hollow panels are completely impervious to moisture. They do not absorb water on wet construction sites, maintain flatness through repeated wet-dry cycles, and will never suffer glue-line failure because there is no glue line — the core and skins are fusion-bonded during co-extrusion.

5. Multi-Functional On-Site Workability

PP formwork panels can be nailed, sawed, and drilled with standard woodworking tools. Contractors do not require specialized cutting equipment or training, enabling flexible on-site adaptation to complex formwork geometries without pre-fabrication delays.

6. Corrosion-Resistant, Flame-Retardant & Thermally Insulating

Modified PP compounds used in CX series production incorporate flame-retardant additives meeting construction site safety codes. The material resists acid and alkali attack from fresh concrete, and its closed-cell hollow structure provides thermal insulation that helps maintain concrete curing temperatures in cold-weather pours.

7. Twin-Screw Co-Extrusion Three-Layer Structure

The CX series' dual-extruder architecture enables true three-layer composite panel production in a single pass: a lightweight hollow core for mass reduction flanked by dense, high-strength surface skins. This design optimizes the strength-to-weight ratio far beyond what single-layer extrusion can achieve, reducing raw material consumption while meeting or exceeding load-bearing specifications.

8. Fully Automated PLC-Controlled Operation

From raw material feeding to finished panel stacking, the entire CX production line runs under centralized PLC control with a color touchscreen HMI. Operators set panel dimensions, line speed, and cutting length via recipe-based parameter management. Once running, the line requires only periodic quality checks — no continuous manual intervention — dramatically reducing labor costs and eliminating operator-induced variability.

9. Environmentally Sustainable & Recyclable

PP hollow formwork is 100% recyclable at end of life. Off-spec panels and edge trims can be ground using a plastic grinding machine or fed through a plastic crusher and reintroduced into the extrusion process as regrind. This closed-loop recyclability, combined with the elimination of timber consumption and reduced steel formwork manufacturing energy, positions CX series formwork as a genuinely green building material solution.

10. Flexible Customization Options

The CX platform supports both single-layer extrusion (one extruder) and three-layer twin co-extrusion (two extruders). Panel widths and thicknesses are adjustable within the machine's design envelope, and standard construction formwork sizes — 915×1830 mm and 1220×2440 mm — are available as pre-configured die head options. Additional customization for core-cell geometry, surface texture, and additive packages (UV stabilizers, colorants, reinforced fillers) is available upon request.

How It Works — PP Hollow Formwork Co-Extrusion Process

The CX series transforms PP modified compound granules into finished hollow formwork panels through a continuous seven-stage process:

Stage 1: Material Feeding
PP modified compound granules are loaded into two conical hoppers via a screw feeder / automatic feeding system. The main hopper supplies the core-layer compound; the auxiliary hopper feeds the surface-layer material. Gravimetric or volumetric dosing ensures precise layer-thickness ratios.

Stage 2: Twin-Screw Plasticization
Inside the SJ-series extruder barrels, co-rotating twin screws convey, compress, shear, and melt the PP compound through precisely controlled temperature zones (typically 180–230 °C). The intermeshing screw profile ensures homogeneous melt quality and thorough dispersion of fillers, flame retardants, and processing aids.

Stage 3: Hollow-Core Die Forming
Molten polymer from both extruders converges in the multi-manifold die head. Internal mandrel structures create the hollow-core geometry — either honeycomb (hexagonal cells) or tubular (parallel cylindrical channels) — while surface-layer melt is distributed evenly across both faces. The die head's flow-channel design is the single most critical engineering element determining panel flatness and core uniformity.

Stage 4: Calibration & Cooling
The extruded web passes through a series of water-cooled calibration plates that set final thickness and surface finish. Spray bars and immersion tanks provide additional cooling capacity, bringing the panel temperature below the PP heat-deflection threshold before the haul-off section. An industrial chiller supplies temperature-controlled cooling water for consistent heat removal.

Stage 5: Haul-Off & Tension Control
Multi-roller haul-off units grip the panel top and bottom surfaces, pulling at a precisely controlled speed synchronized with extruder output via servo feedback. This constant-tension pulling prevents sag, maintains thickness uniformity, and eliminates the "pulse" artifacts common in less sophisticated lines.

Stage 6: Automatic Cut-to-Length
A servo-positioned flying saw traverses with the moving panel, executing clean cross-cuts at programmable intervals. The cutting station is enclosed with dust extraction, keeping the shop floor clean and protecting downstream equipment from particulate contamination.

Stage 7: Automatic Stacking
Pneumatic grippers transfer cut panels onto a stacking platform, building orderly pallets of finished formwork sheets. The stacking pattern (flat, alternating orientation, edge-protected) can be configured to match downstream packaging and logistics workflows.

End-Product Applications & Market

Construction Formwork — The Core Application

PP hollow formwork panels produced on CX series lines serve as the concrete-contact surface in cast-in-place concrete construction. They form the temporary molds into which fresh concrete is poured, vibrated, and cured before the formwork is stripped away, revealing the finished structural element.

Primary Applications:

• Floor slab formwork for multi-story residential and commercial buildings

• Wall formwork for shear walls, retaining walls, and basement enclosures

• Column formwork for structural columns of all cross-sections

• Bridge deck formwork for highway and railway bridge construction

• Precast component molds for factory-produced beams, stairs, and facade panels

• Highway guardrail foundation formwork

Competitive Advantage vs. Traditional Formwork Materials

The economic case for PP hollow formwork is strongest in mid-to-high-rise projects where reusability directly multiplies cost savings. A panel reused 50 times at a material cost only 2–3× that of plywood delivers a per-pour cost that plywood simply cannot match — all while eliminating plywood's inherent quality degradation curve.

Market Drivers

Several global trends are accelerating adoption of PP hollow formwork:

• Timber supply constraints and price volatility in major construction markets (Southeast Asia, Middle East, Africa)

• Green building certification requirements (LEED, BREEAM, Green Star) favoring reusable, recyclable formwork

• Labor shortages driving demand for lightweight, easy-to-handle formwork that reduces crane dependency

• Government mandates in several countries restricting or taxing single-use timber formwork in large-scale projects

• Precast concrete industry growth requiring consistent, dimensionally stable mold surfaces

Why Choose Chenxing Machinery CX Series Formwork Lines

Proven Extrusion Engineering Heritage

Chenxing Machinery brings decades of plastic extrusion expertise to every CX series line. Our engineering team draws from deep experience across our sheet extrusion line platform, pipe extrusion solutions, and pelletizing systems — ensuring that every subsystem in the CX formwork line benefits from cross-domain design knowledge.

Integrated Ecosystem Advantage

Unlike machinery suppliers who offer a standalone extruder, Chenxing provides a complete upstream-to-downstream ecosystem. From raw material preparation — high-speed mixer, disc grinding pulverizer, vibrating screen — to end-of-line ancillaries like industrial chillers, we deliver a true turnkey solution.

Custom Die Head Engineering

The hollow-core die head is the single most critical component determining panel quality. Chenxing engineers each die head to customer specifications — cell geometry, wall thickness distribution, flow-channel optimization — using computational fluid dynamics (CFD) simulation before machining. This engineering investment pays off in faster commissioning, lower scrap rates, and longer die service life.

Global After-Sales Support

Chenxing provides remote commissioning guidance, on-site technician dispatch options, spare parts catalog with express shipping, and ongoing process optimization support. Our engineering team remains accessible throughout the machine's service life, not just during the warranty period.

Frequently Asked Questions

Q1: What is the expected output capacity of the CX series PP hollow formwork extrusion line?

The CX120/75 configuration delivers 450–500 kg of finished panel output per hour under continuous operation, while the CX150/80 achieves 550–600 kg/h. In practical terms, this translates to approximately 80–110 standard 915×1830×15mm panels per hour for CX120/75 and 100–130 panels per hour for CX150/80, depending on panel thickness and core density settings. Actual output is influenced by compound formulation (filler loading affects throughput), ambient conditions, and operator proficiency during commissioning. The PLC system logs real-time production data, allowing fabricators to track and optimize hourly output against theoretical maximums.

Q2: Can the CX series produce panels with different core structures?

Yes. The hollow-core die head is engineered with interchangeable mandrel inserts that define the internal cell geometry. Standard configurations produce either honeycomb (hexagonal) core or tubular (parallel cylindrical channel) core structures. Honeycomb cores offer the best strength-to-weight ratio for floor slab formwork applications where bending stiffness is critical, while tubular cores provide superior crush resistance for heavy-load wall formwork. Custom core geometries — modified cell sizes, variable wall thicknesses, or hybrid patterns — can be developed during the die engineering phase to match specific load-bearing specifications. The die head is a significant one-time investment, so we recommend finalizing core specifications during the quoting stage.

Q3: What raw materials are compatible with the CX series?

The CX series is designed for PP (polypropylene) modified compounds — typically PP homopolymer or copolymer base resin compounded with mineral fillers (talc, calcium carbonate at 20–40% loading), impact modifiers, flame-retardant additives, and processing aids. Recycled PP content of up to 30% can be incorporated without significant property degradation when properly formulated. The twin-screw extruders can also process PP/PE blends and PP/GF (glass fiber) compounds at lower filler percentages, though we recommend trial runs for formulations outside standard PP modified compound specifications. In-house regrind from edge trimming and off-spec panels can be reintroduced at controlled ratios; we typically recommend a plastic crusher and plastic grinding machine combination for efficient size reduction.

Q4: How does the three-layer co-extrusion structure benefit formwork panel performance?

Three-layer co-extrusion enables independent optimization of each layer's formulation. The surface layers (typically 1–2 mm each) can be formulated for maximum surface hardness, smoothness, and concrete-release properties, while the core layer — comprising 70–80% of total thickness — focuses on lightweighting through hollow-cell geometry and cost optimization through higher filler loading. This layered approach means expensive surface-enhancing additives are concentrated where they deliver value rather than being dispersed throughout the entire panel cross-section. Additionally, the fusion bond formed during co-extrusion is permanent and monolithic — there are no adhesive layers that can fail under moisture or thermal cycling, a common failure mode in laminated wood-plastic composite formwork.

Q5: What is the typical commissioning timeline for a CX series line?

From delivery to first commercial production, a typical commissioning timeline spans 4–6 weeks: Week 1 — mechanical installation and utility connections (power, water, compressed air); Week 2 — electrical commissioning, PLC I/O checks, and subsystem dry runs; Week 3 — cold commissioning with polymer, die-head tuning, and first panel production; Weeks 4–6 — process optimization, operator training, and production ramp-up to nameplate capacity. This timeline assumes the customer has prepared the factory floor (level concrete pad, overhead crane or forklift access, adequate power supply) prior to machine delivery. Chenxing provides a detailed pre-installation checklist and can dispatch a commissioning engineer to supervise the process.

Q6: What after-sales support does Chenxing provide for CX series lines?

Chenxing's after-sales commitment includes a standard 12-month warranty on mechanical and electrical components (excluding wear parts such as screws, barrels, heating bands, and cutting blades), remote technical support via video call and messaging during the customer's business hours, an online spare parts catalog with express international shipping (DHL/FedEx), and optional extended warranty packages. For critical spare parts — die head inserts, screw elements, drive belts, PLC modules — we recommend maintaining an on-site inventory based on a recommended spare parts list customized to your production volume. Our engineering team also offers periodic process audits (remote or on-site) to help optimize output, reduce scrap, and extend component service life.

Inquiry & Quotation — Get Your CX Series Formwork Line

Step 1: Define Your Requirements

Tell us your target panel dimensions (width × length × thickness), desired hourly output, core structure preference (honeycomb or tubular), and any special formulation requirements. The more detail you provide, the more accurate our quotation and production timeline estimate will be.

Step 2: Receive a Tailored Proposal

Our engineering team will prepare a customized line configuration including extruder sizing, die head design, auxiliary equipment selection, factory layout drawing, and a comprehensive commercial quotation — typically within 3–5 working days.

Step 3: Factory Visit & Sample Validation

Visit our manufacturing facility in Zhangjiagang, China, to see CX series lines in assembly and witness sample panel production on your specified compound. We can also arrange visits to reference customer sites operating CX formwork lines in production.

Step 4: Order Confirmation & Production

Upon order confirmation with 30% advance payment, production commences with a typical lead time of 60–90 days depending on line configuration complexity. We provide regular production-status updates with photos and milestone confirmations throughout the build.

Contact Nicole directly to start your inquiry:

• Phone/WhatsApp: +86 15951187228

• Email: ceo@cxsljx.com

• Company: Zhangjiagang Chenxing Machinery Co., Ltd.

• Website: www.chenxingmachinery.com