Most PVC lines get bought twice: once at the quoted price, and again on everything that price left out. Here is the order we would plan in, if it were our own money.
4,800 h
Realistic running hours a year
65 mm
Where most strip lines start
15–20%
Of budget is working capital
A curtain strip line and a rigid sheet line are not the same animal, and neither is a 300-tonne plan and a 900-tonne one. What follows is the sequence we walk through with buyers before a single machine is specified, including the parts that never appear on a quotation.
01 / OUTPUT FIRST
The product decides the line, not the other way round
◆Curtain strip, 200 mm wide, 1–3 mm.Single screw, sheet die, haul-off, winder. Calendering is not a serious option under about 600 kg/h.
◆ Rigid sheet, 1–6 mm.Twin screw or single screw plus a three-roll calender. Different budget, different footprint, different operator skill.
◆Food wrap. Line cleanliness, migration compliance, and film tolerance decide the screw and the additive package long before output does.
So write the spec first: width, thickness range, colour, surface finish, roll size, packing. A line sized around a vague "PVC sheet" gets rebuilt within two years, and the rebuild costs more than the original machine.
02 / CAPACITY
Work backwards from tonnage, not from nameplate output
Nameplate figures are measured on a good day, with a warm die and a compound the factory already knows. Plan with effective hours instead.
| kg/h needed = annual tonnes × 1,000 ÷ (days × shifts × hours × 0.80) |
Target output kg/h needed Typical configuration
150 t / year 31 45 mm single screw, manual winder
300 t / year 63 55–65 mm single screw, semi-automatic
600 t / year 125 65–75 mm, automatic winding, second die
1,200 t / year 250 80 mm twin screw with calender, full automation
Based on 300 working days, two 10-hour shifts, 80% uptime. Uptime is where plans fail: budget 80%, never 95%.
03 / THE SITE
Floor, power, water and air decide more than the extruder
We are called into more buildings than boardrooms. Half the delays we see are concrete and copper, not machinery.
Table 02 - Site requirements for a 65 mm line
Item Rule of thumb Why it bites
Clear run 8 m straight, die to winder Turning a warm strip 4 m out gives you permanent curl
Floor area 150–250 m² with resin storage Cheaper to rent 50 m² more than to move a line later
Installed load 60–90 kW Transformer sized at 1.5× installed, or the first cold start trips the plant
Cooling water 3–5 m³/h circulating, 5–10 HP chiller Warm water in July shows up as dimensional drift, not as a fault
Compressed air 0.6 m³/min at 0.7 MPa, dried Wet air destroys cylinders and solenoid valves within a season
Ceiling height 4.5–5 m at the hopper Dryer plus loader stack; nobody measures this until the crane arrives
04 / COMPOUND
Two identical lines, two compounds, two different businesses
The machine is a pump and a heater. What comes out of it is decided by the formulation, and the formulation is decided by where you sell.
◆Stabilizer. Lead-based is cheap and still permitted in some markets. Ca/Zn or tin is what EU and US buyers accept. Choose by destination, not by price per kilogram.
◆Filler.20–40 phr calcium carbonate cuts cost and adds stiffness. Past 50 phr, you are selling chalk with a straight face, and the customer finds out in month three.
◆Plasticizer.30–60 phr for flexible strip. The strip that cracked in a Canadian January was a plasticizer question, not a machine question.
Ask any supplier for the starting formulation and a trial report before you sign. If the answer is "our engineer will handle it on site", you have bought a machine and rented a hope.
05 / BUDGET
Where the money actually goes
Item Share of project Note
Extruder, die, downstream 45–55% The part every buyer negotiates hardest
Mixer, compound prep 10–15% Skipped most often; reappears as thickness drift
Chiller, air, transformer 8–12% Local contractor, usually underestimated
Freight, installation, commissioning 8–12% One 40HQ, flights, 10–14 days on site
Spare screw, die, wear parts 5–8% Cheaper than a two-week shutdown
Working capital, 60–90 days 15–20% Resin before the first invoice is paid
The machine is the cheap part.
Compound, power supply, and ninety days of raw material are what decide whether the line makes money. Projects we are asked to rescue were almost always under-budgeted here, not over-built there.
06 / ACCEPTANCE
What to test before you release the balance
Test Pass mark
Output at rated thickness Within 5% of quoted kg/h, held for 4 consecutive hours
Thickness across the width ±5%, measured at five points, not just the middle
Energy per kilogram Record kWh/kg. It is the only number you can compare between suppliers
Scrap on the first shift Under 8%, and falling by the end of the week
Changeover to a second die Under 4 hours, done by your own crew, not the installer's
Five things that should end a conversation early：
╳No die drawing before the deposit, only photographs of a similar machine
╳"Formula included" with no written formulation and no trial report
╳Commissioning by video call, with no engineer on site
╳A price per set that quietly excludes haul-off, chiller, or electrical panel
╳A delivery date that ignores Spring Festival, then slips six weeks
Send us the product spec, the target tonnage, and a photograph of your power supply. We will come back with a line configuration, a compound starting point, and the site requirements, before anyone mentions price.
