Choosing the right blown film machine output is not about buying the biggest kg per hour number. It is about selecting a line that can achieve your target production reliably, with your resin, your film thickness range, and your quality requirements.
This guide shows a simple method to choose blown film machine output and film blowing machine capacity. Some buyers may also search “film blown machine output,” but the decision is the same: pick a capacity that produces saleable film consistently, not just a short-term peak.
Quick answer: how to choose blown film machine output capacity
Use this 3-step method:
- Define your product: resin type, film width, thickness range, and daily target.
- Set a saleable kg per hour target based on real running hours.
- Check the bottleneck: output is limited by cooling, haul-off, winding, and stability as often as by the extruder.
| Your situation | What it means | What to do |
|---|---|---|
| You know your target kg per day | You need a saleable kg per hour number | Divide by realistic effective hours |
| You change thickness or resin often | More downtime and scrap | Add more capacity margin |
| Tight thickness tolerance is required | Stable speed is lower | Prioritize gauge stability and cooling |
| Thin film at high speed | Cooling and winding limit output first | Do not size by extruder alone |
| You want future expansion | Output must be scalable | Choose balanced upgrades, not only a bigger extruder |
What is blown film machine output in kg per hour
Suppliers may use “output” to mean different things. Clarify the definition before comparing quotes.
Extruder throughput and net film output
- Extruder throughput is how much resin the extruder can melt and push through the die, usually in kg per hour.
- Net film output is production after typical losses such as edge trim, start-up tuning, and short stops.
Two machines with similar extruders can deliver different net output if their cooling and tension control are different.
Saleable output and quality yield
Saleable output is what you can ship: film that meets thickness tolerance, roll quality, and customer requirements. This is the number your business plan should depend on.
Buyer tip: ask suppliers to state output together with test conditions such as resin grade, thickness, width, cooling configuration, and continuous run time.
Output planning workflow for film blowing machine capacity selection
If you are not an engineer, start with simple inputs. You only need a few numbers to get a realistic capacity range.
Key inputs you need to estimate capacity
- Resin and structure: LDPE, LLDPE, HDPE, or multilayer. Note recycled content if planned.
- Film width: layflat width or converted width requirement.
- Thickness range: in microns, such as 15 to 25 microns or 30 to 60 microns.
- Production target: kg per day, rolls per day, or tons per month.
- Quality level: basic packaging film or tight tolerance film with stricter gauge and roll requirements.
How to convert daily production into kg per hour
Do not divide by 24 unless you run 24 hours with almost no stops.
Use effective production hours:
- scheduled running hours
- minus start-up and tuning time
- minus roll change, screen change, and material change time
- minus unplanned downtime
A practical planning formula is:
Required saleable kg per hour = daily target ÷ effective production hours
If your effective hours are lower, your required kg per hour is higher.
How to estimate output from film width and thickness
You do not need a perfect calculation to buy the right machine. You need an estimate that prevents underbuying and explains where the real limits come from.
A beginner friendly output estimation approach
Output increases when line speed increases. But speed is limited by:
- cooling capacity
- bubble stability and gauge control
- haul-off tension stability
- winding stability and roll change efficiency
If you are unsure about line speed, that is normal. In early planning, choose output mainly from your daily target and then apply real-world loss factors in the next section.
Material density and multilayer effects
Different resins have different densities, so the same width and thickness can produce different weight output.
Multilayer lines can deliver better film properties, but saleable output depends heavily on stability. For many products, stable production matters more than peak throughput.
Why nameplate output often differs from real factory output
This is the most common reason buyers feel disappointed after installation: the machine can reach a number during demonstration, but real production is lower.
Scrap and trimming reduce effective output
In real production, you will have:
- edge trim and start-up waste
- bubble breaks or tuning waste
- off-spec film during changes
If you do not account for scrap, you will miss monthly targets even if the machine meets a headline kg per hour number.
When changeovers and screen packs reduce uptime
Frequent roll changes, thickness changes, and material changes reduce effective hours.
Filtration and screen packs also matter. As screens load, pressure rises and stability can change. In some cases you must slow down or stop to change screens, which reduces net output.
Main bottlenecks that limit high speed output
High output is a system result. If one part cannot keep up, saleable output drops.
Extruder limits: screw design and melt stability
Extruder capacity depends on screw design, drive stability, temperature control, and filtration back pressure. Even if a line can push more resin, unstable melt delivery may force slower operation to protect quality.
Die limits: gauge control and bubble stability
The die influences thickness uniformity and bubble stability. If you need tight gauge, your practical output limit may come from stability and control, not from the extruder motor size.
Cooling capacity sets the line speed ceiling
In many thin film applications, output is limited by cooling because you need higher speed to reach your kg per hour target.
Air ring performance and stable speed
Air ring design affects how quickly the bubble cools and stabilizes. Better cooling can support higher stable speed and better thickness consistency.
IBC benefits for higher stable output
IBC can improve cooling efficiency and bubble stability for many applications. When suppliers claim high output, ask what cooling configuration was used and whether that setup is included in your quotation.
Haul-off tension and winding systems determine saleable output
Even if the extruder and cooling are strong, you still need stable rolls. Poor roll quality reduces saleable output and creates downstream complaints.
Tension stability and drawdown behavior
Unstable haul-off tension can cause thickness variation, wrinkles, and poor roll formation. Stable tension control helps keep output high without sacrificing quality.
Winder selection and roll change efficiency
Winding impacts both quality and uptime. If you change rolls frequently, winding design and roll change time directly affect net output.
Recommended output approach by application and resin type
You do not need exact numbers to make a smart decision. Match your output strategy to the product type.
Thin bag film: output is often limited by cooling and winding
Shopping bags and garbage bags require thin film and high speed. Cooling, tension control, and winding stability usually limit saleable output first.
HDPE and high blow up ratio: stability limits speed
HDPE and high blow up ratio production can be less forgiving. Bubble stability and gauge control may limit speed. Ask for proof of continuous stable production at your target thickness range.
Supplier comparison checklist for output test conditions
This checklist helps you compare offers fairly.
What data proves continuous output over eight hours
Ask suppliers for:
- resin type and grade used
- thickness and width during the test
- blow up ratio and configuration summary
- cooling setup details
- continuous run time
- scrap assumptions
- evidence of stable winding and roll quality
If a supplier cannot provide test conditions, treat the output number as a reference, not a production guarantee.
RFQ questions to compare capacity and support
- What is the saleable output under my thickness range
- What configuration is recommended to reach that output reliably
- What is included for cooling, winding, and stability
- Typical energy consumption range during production
- Commissioning, training, and service support
- Spare parts and service response lead time
Are you looking for a reliable blown film machine manufacturer
If you want help choosing output capacity, Wilson Machines can support you as an output planning partner, not just a machine seller.
At Wilson Machines, we help buyers translate film requirements into a realistic saleable kg per hour target and a balanced configuration plan. The goal is stable production that matches your product and operating conditions.
How Wilson Machines helps you choose the right capacity
Share your resin type, film width, thickness range, and daily target, and we can help you:
- estimate a realistic saleable kg per hour target
- identify which module will limit output first
- recommend a configuration path that fits your budget and growth plan
What information to send for a faster quotation
To get a useful quotation quickly, send:
- resin type and recycled content plan
- film width range and thickness range
- daily or monthly production target
- application type such as bag film, packaging film, or HDPE film
- power supply and workshop height if known
Avoid overbuying or underbuying output capacity
Underbuying leads to overtime and missed delivery plans. Overbuying increases investment cost, energy use, and start-up waste.
A smart output choice:
- meets today’s target with stable quality
- leaves room for real-world losses
- supports future expansion with balanced upgrades
Conclusion
To choose blown film machine output, define your film requirements, convert your production plan into a realistic saleable kg per hour target, allow for scrap and downtime, and check the true bottleneck modules such as cooling, haul-off, and winding.
If you want a capacity recommendation based on your film spec, Wilson Machines can review your requirements and suggest a realistic output range for continuous production.
FAQ
1) What is the blow-up ratio (BUR) in film blowing, and how do you calculate it from layflat width?
BUR is the ratio of the inflated bubble diameter to the die diameter. The basic formula is: BUR = Bubble Diameter ÷ Die Diameter.
On the shop floor, you often measure layflat width (the flattened tube). You can convert layflat width to bubble diameter using:
Bubble Diameter ≈ (2 × Layflat Width) ÷ π, then divide by die diameter to get BUR.
Practical tip: measure layflat after the bubble is stable (not during start-up), and keep units consistent (mm with mm).
2) What is Draw Down Ratio (DDR), and why does it matter for output and gauge stability?
DDR describes how much the melt is stretched in the machine direction as it’s pulled and thinned. It strongly affects thickness stability, neck-in/instability risk, and how fast you can run before you get vibration, gauge variation, or breaks. Many blown film calculation guides treat DDR as a key control parameter alongside line speed and bubble geometry.
Real-world takeaway: if you push DDR too aggressively to chase kg/h, you may gain short-term output but lose saleable output due to gauge issues and waste.
3) How can I estimate film output (kg/h) from line speed, film thickness, and width?
A practical estimation uses the relationship between geometry, line speed, and density. Many calculators and guides convert dimensions + melt density + line speed into throughput in kg/h.
In planning, don’t chase perfect precision—use it to set a capacity range. Then validate with the supplier’s test conditions (resin, thickness, width, cooling setup, continuous run time).
4) What scrap rate should I assume when planning “real” output for a blown film line?
For planning purposes, many plants use a scrap + trim allowance instead of assuming perfect yield. Typical experience ranges (varies by product mix and operator skill):
- 2–5%: stable products, fewer changes, mature operators
- 5–10%: frequent thickness/resin changes, thin film at high speed, new line start-up period
If you’re launching a new product or line, plan the first weeks on the higher side, then tighten after the process stabilizes.
5) How much downtime should I budget for roll changes and material changes when converting kg/day to kg/h?
A “paper” 24-hour plan rarely equals real production. A practical budgeting approach is to plan effective production hours. In many factories:
- roll changes: often a few minutes to ~10 minutes each depending on winder type and operator skill
- material or thickness changes: can consume tens of minutes including tuning and waste
If your product mix changes a lot, you will get better accuracy by planning on 16–22 effective hours/day for 24-hour operations (or proportionally less for single shift lines), then updating the number after a week of actual data.
6) How do screen packs and filtration reduce output, and what should I ask suppliers to prove?
As screens load, melt pressure rises and flow stability can change—this may force you to slow down or stop for a screen change. Output also depends on resin cleanliness (especially with recycled content). Output-capacity selection guides routinely list filtration and back pressure as real contributors to “capacity vs reality.”
What to ask in RFQ:
- What screen changer type is included (manual/continuous)
- Under what conditions was the claimed output tested (clean resin vs recycled blend)
- What is the typical pressure range during stable production
- How long a continuous run they can demonstrate at your thickness range (video/data)
7) What causes melt fracture (sharkskin) in blown film, and what are the fastest fixes?
“Melt fracture” (often called sharkskin) is commonly linked to high shear at the die and process conditions such as low melt temperature or too narrow die gap. A common troubleshooting approach is to adjust melt temperature and/or die conditions rather than only changing speed.
Fast, practical checks operators use:
- Verify real melt temperature (sensor placement and control accuracy)
- Adjust melt temperature within resin limits
- Review die gap / die condition and cleanliness
- Reduce excessive output rate if shear is the trigger
If you see a sudden onset after maintenance, also check thermocouples/heaters and die lip condition.
8) How do I verify a supplier’s “kg/h output” claim is continuous, not a short demo?
Ask for proof of continuous stable production—for example an 8-hour run at your target thickness range, with roll quality and scrap assumptions stated. Many buyer guides emphasize that “capacity” must align with your product spec and stability requirements, not just a peak number.
Best practice questions:
- resin grade + thickness + width + BUR used in test
- cooling configuration (air ring/IBC) used in the test
- video showing stable bubble and winding over time
- how they measured output (gross vs net vs saleable)
9) Does IBC always increase output, and when is it worth it?
IBC is mainly about cooling efficiency and bubble stability, which can allow higher stable line speed for some products—especially thinner films where cooling is the ceiling. Cooling is frequently highlighted as a limiting factor in blown film calculations and line sizing discussions.
When IBC tends to be most valuable:
- thin film at higher speeds
- products that are sensitive to gauge variation
- lines where stability (saleable output) matters more than peak output
It’s not automatically “better for every product,” so always compare with your thickness range and quality requirement.
10) What changes when planning output for HDPE vs LLDPE/LDPE film?
Two practical differences:
- Density difference changes the weight output for the same geometry (width/thickness/speed).
- Process window and stability can feel different, so the “peak kg/h” may not translate to stable saleable output at thin gauges or higher BUR settings. BUR calculation and control are central in film blowing because they influence orientation and stability.
If you’re switching resin families, ask the supplier to validate output using the same resin type you plan to run.
