Machine Grade Cling Film: Specs for Tray Overwrappers

Quick answer: Machine grade cling film and hand-wrap cling film are usually the same polymer and very different products. What separates them is consistency — ±5% thickness tolerance instead of ±10-15%, a controlled coefficient of friction, and cling force tuned to the low end of the usable band so the roll unwinds cleanly at 30-60 packs a minute. Most “the film is bad” complaints on an automatic tray overwrapper trace back to four things: worn PTFE tape on the sealing plate, a plate running 10-20°C too hot, actual gauge below nominal, or a roll whose outer diameter never fitted the machine in the first place. This guide gives you the numbers to specify film that runs, and a fault table to diagnose it when it doesn’t.

We extrude and calender PVC and PE food film in the Ningbo Qianwan New Area, 40 km from Ningbo-Zhoushan port, and have supplied supermarket and food-processing customers in more than 50 countries for over 20 years. This article exists because of a pattern we see constantly: a buyer sources cling film on price per kilo, loads it into an Omori or ULMA or Ilpra overwrapper, gets 8% rewrap rate, and concludes Chinese film is poor quality. Nine times out of ten the film was never specified as machine film. Nobody asked.

Hand-Wrap Film and Machine Film Are Not the Same Product

A person pulling film off a cutter box is a remarkably forgiving machine. They feel the film grab, they slow down, they re-pull, they press the fold with a thumb. An automatic overwrapper does none of that. It applies a fixed unwind tension, a fixed stretch percentage and a fixed plate dwell, thousands of times an hour, and any variation in the film shows up as a reject.

	Hand-wrap film	Semi-automatic film	Full-automatic machine film
Thickness tolerance	±10-15%	±8%	±5% or tighter
Cling force	High — sells on “sticks best”	Medium	Medium-low, tightly controlled
COF (film/metal)	Not specified	Loosely specified	Specified and batch-tested
Core ID	1” (25.4mm)	1” or 1.5”	1” or 3” (76mm), machine-matched
Roll length	30-300m	300-600m	600-1,500m
Edge quality	Cosmetic	Important	Critical — edge nicks cause web breaks
Typical price premium	Baseline	+1-3%	+3-6%

That last line is the point of the whole table. Machine grade film is not an exotic material and it does not cost 30% more. It costs a few percent more because it comes off a line that is running tighter process control and a slitter that is being re-bladed more often. If a supplier quotes you machine film at exactly the same price as hand film, they are selling you hand film.

There is one genuine trap here. Buyers who have read that a stickier film performs better — and it does, for hand wrapping, as we covered in our guide to cling force — sometimes specify maximum cling for a machine line. On an overwrapper this backfires. Film that bonds hard to itself on the roll needs a higher unwind torque to release, the higher torque stretches the web before it reaches the tray, and the stretched web then shrinks back off the fold as it cools. You get open packs from film that is too good at clinging.

The Six Numbers Your Overwrapper Actually Cares About

Here is what belongs on a machine-film specification sheet, what to expect, and what breaks when it drifts. Test methods are given because a number without a method is not a specification.

Property	Method	Typical for PVC overwrap film	What goes wrong if it drifts
Thickness + tolerance	ASTM D6988 / micrometer, 5 points across web	9-12 µm produce, 12-17 µm meat, ±5%	Thin: burn-through at the plate. Thick: cold seals, film cost up
Elongation at break (MD)	ASTM D882	150-350%	Low: web breaks on the stretch belts. High: film necks and wrinkles
Tensile strength (MD)	ASTM D882	40-70 MPa	Low: tears at the folder blade under bone-in trays
Peel cling / self-adhesion	ASTM D5458	1.5-4.0 N/25mm, controlled band	High: hard unwind, stretch-back, open packs. Low: fold pops
Coefficient of friction (film/metal)	ASTM D1894	Kinetic 0.25-0.45	High: film grabs the belts and skews. Low: film slips, no stretch
Elmendorf tear (TD)	ASTM D1922	15-60 g	Low: an edge nick propagates into a full web break

Two of these are almost never on Chinese quotations unless you ask by name: coefficient of friction and peel cling measured as a band rather than a minimum. Ask for both. A supplier who can produce a COF result to ASTM D1894 has a lab; a supplier who cannot is selling you whatever came off the line.

The other under-specified figure is thickness measured as actual, not nominal. The single most common quality dispute we see is a buyer who ordered 9 micron, received film that measures 7.6-8.2 micron, and cannot understand why the plate temperature that worked for years now burns through. Thinner film is cheaper per square metre, so the incentive to shave gauge is permanent across the industry. Specify a tolerance, specify the method, and check incoming rolls with a micrometer at five points across the web. Our thickness chart guide sets out the micron-to-mil conversions and application bands in full.

Sourcing machine film and want the numbers checked before you commit? Send us your machine model, tray sizes and current fault rate and we will come back with a specification and a trial roll. Talk to the SUNWRAP export team →

Roll Format: The Spec That Silently Kills Orders

Width and length get quoted. Core inner diameter and maximum outer diameter get forgotten, and they are the two that make a container of film unusable on arrival.

Machine class	Core ID	Roll width	Roll length	Max roll OD
Bench-top / manual hot plate	1” (25.4mm)	250-400mm	300-600m	120-180mm
Semi-automatic tray wrapper	1” or 1.5” (38mm)	300-450mm	600-1,000m	180-220mm
Automatic overwrapper (supermarket back-room)	3” (76mm)	350-500mm	900-1,500m	200-250mm
High-speed processing line	3” (76mm)	400-600mm	1,500-3,000m	250-350mm
Jumbo roll for in-house slitting	3” or 6” (152mm)	600-1,400mm	up to 5,000m	400-600mm

Work the maximum OD backwards before you order. A 450mm × 1,500m roll of 10 micron PVC is roughly 6.5-7 kg and lands near 200mm OD; the same length at 15 micron is closer to 245mm and will not close the film cradle on a machine rated to 220mm. This is arithmetic, not opinion, and it takes two minutes — but it is the reason pallets of perfectly good film sit in warehouses.

Three more format details worth writing into the purchase order:

• Wind direction and core overhang. Specify whether the film pays off over or under the roll, and whether the core is flush or overhangs. Some machines index off the core end.
• Core material. Paper cores absorb humidity in tropical warehouses and go out of round, which shows up as tension surge. Specify a minimum core wall thickness or a plastic core for humid destinations.
• Edge trim. Slit edges must be clean. A single nick in the edge of the web will propagate under machine tension within a few metres. This is where a poorly maintained slitter destroys otherwise excellent film.

For the full width and length matrix across retail, catering and industrial formats, see our cling film roll sizes guide.

The Sealing Plate: Why PVC Dominates Tray Overwrapping

The mechanism of a tray overwrapper is unglamorous and unforgiving. The film is stretched over the tray, four flaps are folded underneath, and the pack is dragged across a heated plate — usually aluminium faced with PTFE tape — which fuses the folds together. Everything about the film has to suit that half-second of contact.

Material	Working plate temp	Self-cling	Fold retention	Suitability for tray overwrap
Plasticised PVC	120-140°C	Excellent	Excellent — low elastic recovery	Industry default
LDPE / LLDPE cling	95-115°C	Fair	Poor — springs back off the fold	Workable on PE-configured machines only
PVDC	130-150°C	Good	Good	Barrier applications, high cost
PLA / compostable	90-110°C	Poor	Poor — brittle at the fold	Marginal; needs a machine built for it

PVC wins tray overwrapping for one structural reason: plasticised PVC has very low elastic recovery. Once it is folded, it stays folded long enough for the plate to reach it. Polyethylene wants to spring back. That is why PE performs so well on pallet stretch wrap, where film-to-film locking under continuous tension is the job, and so poorly under a supermarket meat tray. We set out the full material trade-off in PVC vs PE cling film.

Two hard temperature limits are worth committing to memory. Below roughly 105°C the folds do not fuse and packs open in the chiller, typically eight to twelve hours later, which is why the fault gets discovered on the shop floor rather than in the back room. Above roughly 160°C plasticised PVC begins to degrade and evolve hydrogen chloride, which pits the plate, discolours the PTFE tape and can taint product. If your operators are creeping the plate temperature up to fix a sealing problem, the actual problem is almost always elsewhere in the table below.

Troubleshooting: Is It the Film or the Machine?

This is the section our customers actually print out. Run through it in order before raising a claim — and before assuming your machine needs a service call.

Fault	Most likely cause	Check this first	Film or machine?
Film sticks/burns on the plate	Worn PTFE tape; plate 10-20°C high; gauge below nominal	Replace tape, then drop plate 10°C, then micrometer the film	Machine (usually)
Packs open in the chiller	Plate too cool; dwell too short; cling too low	Raise plate 5-10°C in steps; measure peel cling	Both
Web breaks mid-run	Edge nick from slitting; unwind tension too high; low tear strength	Inspect roll edges under a light; check Elmendorf figure	Film (usually)
Film skews / tracks off	Uneven gauge profile across web; COF too high; belt wear	Micrometer 5 points across web, compare edges to centre	Film (usually)
Roll telescopes on the shaft	Poor rewind tension at the converter; soft core	Push-test the roll face; check core roundness	Film
Hard unwind, film stretches before the tray	Cling force too high; blocking from hot storage	Check storage temperature; request lower cling band	Film
Wrinkles across the tray face	Elongation too high; stretch belts over-tensioned	Reduce stretch %, then check elongation spec	Both
Fogging under the film	No anti-fog additive; chiller cycling	Confirm anti-fog masterbatch is in the spec	Film
Meat turns brown within a day	Film OTR too low for red meat	Check oxygen transmission rate against spec	Film
Static; film clings to machine frame	Low humidity; no antistatic additive	Measure RH in the room; request antistatic grade	Both

Two of these deserve a note. Blocking from hot storage is a real and underdiagnosed problem for buyers in the Gulf, West Africa and Southeast Asia: plasticised PVC stored above roughly 40°C for weeks will migrate plasticiser to the surface and the roll will unwind much harder than it did at the factory. It is not a manufacturing defect, and it is preventable by storing rolls below 30°C, out of direct sun, and rotating stock within 12 months.

Fogging and browning are film-specification issues, not machine issues, and they are the two most expensive faults on this list because they show up as shrink at the retail counter rather than as rejects in the back room. Anti-fog is a masterbatch decision made at the extrusion stage — it cannot be added later. Oxygen transmission for red meat overwrap needs to be high, not low, which is counter-intuitive to anyone used to barrier packaging; we cover the OTR targets in detail in our ventilated and breathable food film guide and the meat-specific requirements in the meat wrapping guide.

Food-Contact Compliance for Machine Film

Machine film carries one compliance obligation that hand film does not: it is heated. Migration testing is only valid inside the time and temperature conditions it was run under, so a declaration of compliance that covers refrigerated contact does not automatically cover a half-second at 140°C plus a warm fold.

Ask for these, by name:

1. Declaration of compliance to EU Regulation 1935/2004 and 10/2011, with the specific migration results for the plasticiser system. DEHA carries a specific migration limit of 18 mg/kg, ATBC 60 mg/kg, ESBO 60 mg/kg, against an overall migration limit of 10 mg/dm².
2. US clearance — confirmation that resin and plasticisers fall under 21 CFR 178.3740 and the related food-additive provisions for the intended contact type.
3. GMP statement under Regulation EC 2023/2006 covering slitting and rewinding, since that is the step where oil and metal particles are most likely to enter.
4. Stated maximum service temperature, and the conditions the migration test was run at. This is the one that is almost always missing.
5. For China-facing and re-export business, GB 4806.6 for the resin and GB 9685 for additives.

If a supplier sends a certificate with no test conditions on it, treat it as marketing. Our food-grade certification guide walks through what each document should actually contain.

Cost, MOQ and Lead Time

Straight numbers, FOB Ningbo, at the time of writing:

Item	Figure
Food-grade PVC cling film, FOB Ningbo	USD 1,100-1,700 / tonne
Machine-grade specification premium	+3-6% over standard hand-wrap film
Anti-fog masterbatch	+2-4%
MOQ	5 metric tons per specification, or one 20ft container for mixed stock SKUs
20ft container capacity, jumbo roll	16-18 tonnes
Lead time, standard specs	15-20 days
Lead time, custom cores / printing / retail packaging	25-30 days
Our monthly capacity	500+ tonnes

The premium is small enough that arguing over it is a false economy. Work it from the other end: at 40 packs per minute on a single shift, a one-percentage-point reduction in rewrap rate is worth several thousand trays a month in labour and material. A 4% film premium pays for itself well before that.

Volume changes the sourcing shape. Above roughly 150-200 tonnes a year, buying jumbo rolls and slitting in-house usually beats buying finished machine rolls — you stop shipping air inside cores and cartons, and you gain width flexibility. Below that, converting labour, blade wear and scrap eat the saving. For the container-volume arithmetic behind that decision, see our container loading guide.

How to Write a Spec Your Factory Cannot Misread

Copy this into your RFQ. It takes one email and removes most of what goes wrong.

• Machine make and model, and maximum roll OD the cradle accepts
• Core ID in mm, core wall thickness, wind direction
• Roll width and length, and target roll weight
• Nominal thickness and tolerance — state ±5% and the measurement method
• Peel cling target as a band, e.g. 2.0-3.0 N/25mm to ASTM D5458, not “as sticky as possible”
• COF requirement to ASTM D1894, film-to-metal, kinetic
• Anti-fog: yes/no. Antistatic: yes/no
• Product being wrapped — red meat, poultry, produce, bakery, ready meals — and storage temperature
• Destination market, so the right compliance package is issued
• Plate temperature you currently run, so we can flag a mismatch before shipping

Send the machine model. It is the single most useful line in the whole document, and it is the one buyers leave out most often.

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Where to go next

• PVC cling film — the standard material for tray overwrapping, with full specifications
• PE cling film — for machines configured for polyethylene overwrap
• Cling film jumbo rolls — for buyers slitting in-house
• Custom and OEM cling film — bespoke widths, cores, anti-fog and printed packaging
• Cling film price guide 2026 — how resin, plasticiser and freight move the FOB number

Running an overwrapper and fighting your film? Send us the machine model, your tray sizes, your current plate temperature and your reject rate. We will tell you whether it is a specification problem or a machine problem — and if it is the film, we will send a trial roll cut to your machine before you order a container. Request a quote for machine grade cling film →