YuanSu, a Wanplas factory, designs and builds complete plastic film, sheet, and board extrusion lines, and the geomembrane and waterproof sheet production systems described here sit at the core of its sheet extrusion program. For more than a decade the engineering team has supplied landfill liner lines, reservoir impermeable membranes, and building waterproof sheets to contractors and membrane converters across the Wanplas group’s exported regions, and the purpose of this article is to explain how a geomembrane extrusion line is actually built, which polymer grade performs best under each site condition, and how a buyer should specify a line that matches real project throughput rather than a generic catalog number. Landfill containment and structural waterproofing are unforgiving applications: a pinhole defect in a primary liner can release leachate for decades, and a roof membrane that separates at a weld can flood an entire building, so the equipment that makes these sheets has to deliver consistent thickness, homogeneous melt, and repeatable surface quality shift after shift. The guidance below is written from the standpoint of machine design and polymer processing, not marketing claims, and it maps directly onto the sheet extrusion lines that YuanSu manufactures as part of the Wanplas family of plastic machinery factories.
How a Geomembrane Extrusion Line Is Built
A geomembrane extrusion line is fundamentally a flat-sheet extrusion system tuned for very wide, relatively thick, and chemically stable polymer sheet. The process begins at the gravimetric or volumetric feeding system, where resin, carbon black masterbatch, and any stabilizer package are dosed at a controlled ratio so that every roll carries the same pigment and antioxidant load. The blended material enters the barrel of a single-screw or co-rotating twin-screw extruder, where the screw conveys, compresses, and plasticizes the polymer while the barrel heaters raise it to a homogeneous melt. For polyethylene geomembranes the plasticizing unit is usually a large-diameter single-screw extruder with a high L/D ratio, because the melt must be fully blended with carbon black yet kept free of degradation. A continuous screen changer removes gel and contamination before the melt reaches the die head, and many lines add a gear-type melt pump to stabilize pressure and therefore stabilize sheet thickness.
From the extruder the melt flows into a flat T-die or coat-hanger die whose lip opening and bolt adjustment set the initial sheet profile. The extruded curtain is then drawn onto a three-roll polishing stack, which both cools and calibre the sheet to its final thickness while imprinting the required surface finish. For landfill geomembranes the surface is frequently textured, either by a post-extrusion embossing roll or by co-extruding a rough skin layer, and the polishing rolls are engineered accordingly. After the polishing stack the sheet passes through a cooling conveyor, an online thickness gauge, edge-trimming knives, and a haul-off system before it is wound on a surface winder into rolls of several hundred meters. Width is the defining constraint for this kind of line: landfill liners are welded on site from panels that can be 7 to 8 meters wide, so the die, roll stack, and winder are built to hold flatness and tension across an unusually large format, and YuanSu sizes the roll-stack length and frame rigidity to keep the sheet flat across the full width.
The control architecture ties every section together. A PLC with HMI manages barrel zone temperatures, screw rotation speed, melt pressure, roll-stack gap, line speed, and winder tension, and recipe management lets an operator recall a stored parameter set when switching from a smooth HDPE liner to a flexible TPO roofing membrane. Closed-loop thickness control uses the online gauge reading to nudge the die bolts and roll gap so the sheet stays inside tolerance without an operator jogging the line by eye. In practice this is what separates a membrane line that holds specification from one that merely looks like it is running, because geomembrane standards are written around measured properties such as thickness, carbon black content, and puncture resistance, and a converter can only meet those numbers if the extrusion line is stable from the first meter of a roll to the last.
Choosing the Polymer for Landfill and Waterproof Membranes
Material selection decides whether a membrane survives its installation and its service life, and the choice is driven by chemical exposure, substrate movement, welding method, and budget. High-density polyethylene, usually written HDPE, is the dominant geomembrane resin for municipal landfill primary and secondary liners because of its outstanding chemical resistance and its ability to be textured for slope stability; it is welded by thermal wedge or extrusion, and it tolerates the aggressive leachate environment better than almost any alternative. Linear low-density polyethylene, LLDPE, is chosen where the substrate flexes or settles, because it stays more flexible at low temperature. Polyvinyl chloride, PVC, is lower cost and easy to weld, and it is common in ponds and some building applications, but it is less resistant to certain hydrocarbons and it contains plasticizer that can migrate over a long service life, so specifiers weigh that trade carefully.
Thermoplastic polyolefin, TPO, has become the leading single-ply roofing membrane because it is weldable, free of plasticizer, and resistant to UV and weathering when properly stabilized. Ethylene-vinyl acetate, EVA, and chlorinated polyethylene, CPE, are widely used for tunnel, subway, and basement waterproofing because they remain flexible and conform to complex shapes, and they are heat-welded on site. The table below summarizes the practical differences that drive line configuration, and it deliberately avoids absolute performance claims because every grade and every stabilization package shifts the numbers; the values shown are representative ranges used for engineering comparison rather than a specification for any single compound.
| Material | Density (g/cm³) | Service Temp (°C) | Chemical Resistance | Typical Application |
|---|---|---|---|---|
| HDPE | 0.94-0.96 | -60 to 80 | Very High | Landfill liner, mining leach pad |
| LLDPE | 0.92-0.94 | -70 to 70 | High | Settling or cold substrates |
| PVC | 1.30-1.40 | -20 to 60 | Medium | Ponds, some roofs |
| TPO | 0.90-0.94 | -40 to 90 | High | Roofing membrane |
| EVA / CPE | 0.93-0.98 | -40 to 70 | High | Tunnel, basement waterproofing |
Additives are as important as the base resin. Carbon black at roughly 2 to 3 percent is standard in HDPE geomembranes because it provides UV protection and a measurable quality marker, and antioxidants protect the melt during plasticizing. A converter that runs several resin families on one line needs a feeding and mixing strategy that prevents cross-contamination and that keeps the masterbatch ratio exact, which is why YuanSu treats the gravimetric feeder and the recipe management system as core parts of the line rather than optional accessories. When a project calls for a reinforced composite, a co-extruded structure can place a tough outer skin over a flexible core, and the line is specified with multiple extruders feeding a multi-layer die so the layers bond in a single pass instead of being laminated afterward.
YuanSu Geomembrane and Waterproof Sheet Lines
Within the Wanplas sheet extrusion portfolio, YuanSu offers dedicated lines for impermeable and waterproof sheet, and the two families that matter most for this discussion are the polyethylene geomembrane line and the thermoplastic waterproof sheet line. Both are built on the same flat-sheet principle described above, but they are optimized for different resins, widths, and surface requirements, and a buyer should understand both before deciding which configuration fits the target market.
PE and HDPE Geomembrane Sheet Extrusion Line
The polyethylene geomembrane line is built around a single-screw extruder sized for the required output, a continuous screen changer, an optional melt pump, and a wide T-die followed by a three-roll polishing stack. It produces smooth or textured sheet in the thickness band used for landfill liners and reservoir caps, and it handles HDPE, LLDPE, and MDPE grades with the appropriate stabilization package. YuanSu’s sheet lines are specified with flatness control of 0.1 mm per meter or better and with online thickness measurement, because liner specifications are written around measured thickness and a converter must be able to prove compliance roll by roll. The representative layout below shows the configurable envelope rather than a fixed model, and exact width, thickness, and output are set when the line is engineered for a specific order.
| Config | Sheet Width | Thickness | Layers | Output |
|---|---|---|---|---|
| Standard HDPE liner | up to 8 m | 0.5-3.0 mm | 1-3 | Medium-High |
| Textured liner | up to 8 m | 1.0-2.5 mm | 2 | Medium |
| LLDPE flexible | up to 8 m | 0.3-2.0 mm | 1-2 | Medium-High |
| Co-extruded composite | up to 7 m | 1.0-3.0 mm | 2-3 | Medium |
TPO, PVC, and CPE Waterproof Sheet Extrusion Line
The thermoplastic waterproof sheet line covers roofing membranes and below-grade waterproofing, and it is tuned for TPO, PVC, and CPE compounds that may include filler, flame retardant, or UV stabilizer. Sheet flatness and surface uniformity matter because these membranes are welded on site and a wavy sheet is hard to seam, so the polishing stack and haul-off are built for tight tolerance. YuanSu positions this line as part of its building and infrastructure solutions, and it shares the same control platform, online measurement, and turnkey delivery model as the geomembrane line, which simplifies spare parts and operator training when a customer runs both product families.
| Config | Sheet Width | Thickness | Layers | Output |
|---|---|---|---|---|
| TPO roofing | up to 3 m | 1.0-2.0 mm | 1-2 | Medium-High |
| PVC waterproof | up to 3 m | 0.8-2.0 mm | 1-2 | Medium-High |
| CPE / EVA tunnel | up to 4 m | 1.0-2.5 mm | 1-2 | Medium |
| Filled composite | up to 3 m | 1.0-3.0 mm | 1-3 | Medium |
Beyond these two families, YuanSu supplies cast film lines for thin waterproof membranes in the 0.008 to 0.25 mm range and thick board lines for rigid protective sheets in the 3 to 50 mm range, so a customer who wants to broaden from geomembrane into adjacent waterproofing products can stay within one supplier and one control philosophy. Where a project needs a reinforced geomembrane, the line is configured with a second extruder feeding a co-extrusion die so a scrim-reinforced or multilayer structure is formed in a single extrusion pass, which is more consistent than bonding layers in a separate lamination step. The technical features that carry across the whole sheet program are flatness control, online measurement, and multi-layer co-extrusion capability, and those are the points a buyer should verify when comparing proposals from different suppliers.
Applications in Landfill and Waterproof Engineering
The membranes made on these lines protect soil, water, and structures, and the application list is broader than most buyers first assume. In solid-waste landfills, HDPE geomembrane forms the primary and secondary liner, the leachate collection barrier, and the final cap, and textured grades are used on slopes where a smooth sheet would slide under the overburden. Mining operations use the same material for heap leach pads and tailings containment, where chemical resistance is the deciding property. Water management projects use impermeable sheet for reservoirs, canals, and aquaculture ponds, and agriculture uses it for irrigation ponds where seepage loss would waste both water and energy.
In civil and building engineering, EVA and CPE membranes line tunnels, subways, and basements because they conform to irregular surfaces and weld reliably in confined spaces, while TPO and PVC sheets cover roofs and podium decks where weather resistance and seam strength determine service life. Industrial plants use chemical-resistant liners for secondary containment around tanks and process pools. Each of these end uses has its own acceptance standard, but they all rely on the same underlying capability: a stable extrusion line that produces sheet of uniform thickness, correct compound, and clean, weldable edges. YuanSu’s industry solutions group the relevant applications under construction and infrastructure, packaging, electronics and new energy, and healthcare and consumer goods, and the waterproof and anti-corrosion segment is the one that pulls geomembrane and sheet lines most directly into engineering projects.
Selecting the Right Line Configuration
Choosing a line should start from the product the customer intends to sell, not from a list of machine sizes. A converter targeting landfill liners needs width above all else and should specify a line built for panels up to 8 meters with texturing capability, whereas a roofing membrane producer cares more about TPO stabilization, surface quality, and roll handling at narrower widths. A tunnel-membrane maker needs flexible compound handling and dependable thin-to-medium gauge control. The recommendation table below maps common requirements to the matching YuanSu line, and it is meant as a starting point for a detailed specification discussion rather than a substitute for engineering the line to the actual resin and output target.
| Requirement | Recommended Line | Key Notes |
|---|---|---|
| Smooth HDPE landfill liner | PE Geomembrane Sheet Line | Width to 8 m, single or multi-layer |
| Textured slope liner | Textured Geomembrane config | Co-extruded rough skin layer |
| TPO roofing membrane | TPO Waterproof Sheet Line | UV stabilized compound |
| Tunnel or basement sheet | EVA / CPE Waterproof Line | Flexible, weldable gauge |
| Reinforced composite | Co-extrusion Sheet Line | Multi-extruder die |
| Thin cushion membrane | Cast Film Line | Sub-0.25 mm gauge |
Output is the second axis of the decision. A higher output line needs a larger extruder, a wider die, and a more robust roll stack and winder, and it also needs more stable upstream feeding and more careful cooling because heat removal scales with thickness and width. YuanSu sizes these elements together rather than bolting a bigger extruder onto a frame that cannot hold the sheet flat, because the weak point in a wide geomembrane line is almost always flatness and edge stability rather than raw melt capacity. Buyers should also plan for the auxiliary side: gravimetric feeders, chiller and mold temperature control for the roll stack, air handling for the trimming system, and a winder matched to the roll diameter and weight the converting operation will actually handle.
Process Parameters and Quality Control
Geomembrane quality is established in the barrel and locked in at the polishing stack, so the process window has to be controlled deliberately. Polyethylene is plasticized in the barrel across a staged temperature profile that rises from the feed zone to the metering zone and then settles at the die so the melt is homogeneous without overheating; exact zone values depend on the resin and the stabilizer package, and they are stored as recipes rather than set by hand for every run. Melt pressure is kept stable by the screen changer and, where fitted, the melt pump, because pressure swings translate directly into thickness variation. The polishing rolls are held at a temperature that gives the right surface and crystal structure without sticking, and the gap is the final thickness setter.
| Parameter | Typical Control | Purpose |
|---|---|---|
| Barrel zone temp | Staged profile | Homogeneous melt |
| Melt pressure | Stabilized | Uniform thickness |
| Roll-stack gap | Closed-loop | Final gauge |
| Online thickness | Real-time gauge | Tolerance control |
| Flatness | 0.1 mm/m or better | Weldability |
Quality control does not stop at the machine. A responsible converter validates carbon black dispersion, thickness across the width, tensile and puncture properties, and seam strength, and the extrusion line supports that work by delivering sheet that is consistent enough to pass. YuanSu builds the line with online measurement and recipe management so that the variation the laboratory sees is small and explainable, and it supplies the process documentation a quality system needs. The Wanplas group’s shared promises cover production capacity and quality standards, and those commitments matter for a buyer who is investing in a line that must run reliably for years on critical infrastructure projects where a failure is expensive and hard to repair.
Service, Support, and Turnkey Delivery
A geomembrane line is a long-term production asset, and the difference between a good purchase and a poor one is often the support that follows it. As a Wanplas factory, YuanSu delivers a structured turnkey path that begins with factory planning and layout, continues through raw material formula development and equipment manufacturing with pre-shipment inspection, and closes with on-site installation, commissioning, trial production, operator training, and ongoing mass-production support. This six-step model is intended to take a customer from an empty building to qualified output without the buyer having to assemble the pieces from unrelated suppliers, and it is particularly valuable for first-time membrane producers who need process know-how as much as hardware.
The shared Wanplas after-sales policy applies to every line, and it includes USD 500 of free spare parts every year together with warranty replacement for damaged parts, an open-factory policy that welcomes customer visits, and a team with deep per-equipment-type experience. For a geomembrane producer this means a realistic path to keeping the line running: wear parts are planned, commissioning is done by engineers who know the machine, and process questions can be raised with the same organization that built the line. YuanSu also offers factory problem solutions covering water and electricity design, site layout in three dimensions, and process system support, so the line is delivered as part of a working plant rather than a machine on a truck.
Field Welding and Installation Compatibility
A geomembrane line is only as good as the seams made from its sheet on the job site, so extrusion quality and weldability are two sides of the same requirement. Thermal wedge and extrusion welding are the dominant field methods for HDPE, and both demand a sheet with uniform thickness, clean edges, and a consistent compound so the weld parameters do not have to be relearned panel to panel. A sheet that varies in gauge forces the welder to chase the setting, and that variation is exactly what online thickness control is meant to suppress at the source. Textured liner needs compatible welding procedure and overlap, and the rough surface must be produced without weakening the underlying core, which is why the texturing step is engineered as part of the line rather than treated as a finish applied afterward.
For roofing and below-grade membranes, hot-air and overlap welding dominate, and surface flatness again decides whether a seam closes cleanly. A converter who controls the roll-stack gap and cooling precisely ships sheet that lays flat on a roof deck or against a tunnel wall, reducing the labor and rework that hidden wrinkles cause. YuanSu’s sheet lines carry the same online measurement and recipe discipline across the geomembrane and waterproof families, so a producer running both product types trains one operator skill set and keeps one spare-parts list. When a project specifies a reinforced or multilayer structure, the co-extrusion approach also helps welding because the weld zone is the same homogeneous material through the thickness rather than a bonded interface that can split, and that consistency is what designers look for when they approve a membrane system for a critical containment or waterproofing application.
Frequently Asked Questions
What thickness of geomembrane is best for landfill liners?
Municipal landfill primary liners are most often specified in the 1.5 to 2.5 mm range, with thicker sections used where puncture or differential settlement is a concern. The right thickness is set by the design standard and the site conditions rather than by the machine, but the extrusion line must hold that thickness uniformly across an 8-meter width, which is why flatness control and online thickness measurement are built into YuanSu geomembrane lines.
Can one line produce both HDPE and TPO membranes?
It can, with the correct configuration. HDPE and TPO are both polyolefins and run on flat-sheet lines, but they need different dies, roll temperatures, and compound handling, so the line is usually set up for one family as the primary product and qualified for the other through stored recipes and adjustable tooling. YuanSu designs its sheet lines on a shared control platform so a converter can move between product families without relearning the machine.
How wide can geomembrane sheets be produced?
Landfill geomembrane lines from YuanSu are built for panels up to about 8 meters wide, because wider panels mean fewer field seams and therefore lower leak risk. Width is limited by die, roll-stack, and winder engineering rather than by extrusion alone, and the frame rigidity that keeps the sheet flat at full width is the part buyers should inspect most closely.
What is the difference between smooth and textured geomembrane?
Smooth geomembrane is used on flat substrates and for easy welding, while textured geomembrane has a rough surface that grips soil and prevents sliding on embankments and caps. Texturing is produced by co-extruding a rough skin layer or by embossing, and it requires a line configuration that adds that capability, which is why YuanSu offers a dedicated textured liner setup within the geomembrane program.
How does the line keep thickness uniform?
Thickness is controlled by stabilizing melt pressure with a screen changer and optional melt pump, setting the polishing-roll gap under closed-loop control, and reading the sheet with an online gauge that adjusts the die bolts and roll gap in real time. YuanSu specifies flatness of 0.1 mm per meter or better so the sheet stays weldable across its full width.
What after-sales support comes with a geomembrane line?
Support follows the Wanplas shared policy: USD 500 of free spare parts every year, warranty replacement of damaged parts, on-site installation and commissioning by engineers, operator training, lifetime consultation, and an open-factory visit policy. The six-step turnkey model also covers formula development, factory layout, and mass-production guidance so the line reaches qualified output.
How long does installation and commissioning take?
The timeline depends on line size, site readiness, and utility preparation, but the structured path keeps it predictable: factory planning and manufacturing happen before shipment, and on-site work focuses on installation, commissioning, trial production, and training. Buyers should prepare water, power, and layout in advance using YuanSu’s factory design support to avoid delays once the equipment arrives.
Work With YuanSu on Your Geomembrane Line
If you are planning a landfill liner, reservoir, or waterproofing membrane production project, the next step is a concrete specification rather than a generic quote. Share your target products, required width and thickness, resin family, and expected output, and YuanSu, a Wanplas factory, will configure a geomembrane or waterproof sheet line to match, including die, roll stack, online measurement, and turnkey installation. You are welcome to visit the factory to review the sheet extrusion program and discuss process details with the engineering team, and to request a trial on representative material so the line is validated against your actual compound before it ships. The Wanplas group’s shared promises on capacity, quality, and spare parts apply to the delivered system, giving you a single accountable partner from layout to mass production.
