A Complete Guide to Mill Size Balers & Bales

Wholesalers, distributors, and manufacturers are all examples of businesses that have significant quantities of cardboard to dispose of as part of their daily operations. If your business produces more than one tonne of cardboard waste each week, a mill size baler is the recommended  type of baler to compact your waste. However, there are some important factors that you must first consider, especially if you want to secure the best return on investment (ROI). This guide will run you through the key points to enable you to decide whether this could be commercially the right opportunity for your organisation.

What is a mill size baler?

A mill size baler, also known as a mill sized baler, is the largest size of vertical waste baler available in the UK. This specialist type of waste baling machinery is designed to mechanically compact high volumes of waste into dense bales securely tied by strong wires. The most common type of waste baled inside this specific size of baler is cardboard however, it's also possible to bale plastics and textiles.

Common uses of mill size balers

Mill size balers are installed in a wide range of commercial and industrial environments in the UK. These include:

• Large warehouses
• Cold storage facilities
• Manufacturing sites
• Distribution centres

Common types of mill size baler

The right mill size baler depends on the working environment and the waste being loaded into it. The two most common types are:

Vertical: The most common type; uses powerful internal hydraulic rams to compact masses of material at once. Excellent for both indoor and outdoor use (providing it's rated IP55)

Horizontal: Designed for sites with high-waste volumes. Primarily installed at very large distribution centres and recycling plants.

Key features of mill size balers

When buying or hiring a mill size baler, there is a wide range of features you should consider:

Compaction forces

Mill size balers operate using hydraulic pressure powered by 3-phase electricity. When choosing a machine, consider its maximum compaction force to ensure it meets your needs. We have balers that achieve up to 39.5 tonnes of force.

Rams

Both single and twin-rammed mill size balers are available.  Some users prefer a machine fitted with a single large diameter ram whereas others prefer a machine equipped with two equally sized smaller rams. Our expert team can advise on the pros and cons of each design.

Machine footprint

One of the standout features of a vertical mill size baler is its small footprint (most are smaller than 2m x 2m) enabling it to be installed close to the source of waste. This makes it perfect for boosting waste handling efficiency. Always access the ceiling height in your building to ensure you're ordering a machine that will fit.

Safety features

All our balers come with a range of safety features to reduce accidents and give you peace of mind. QCR supply balers that meet EN ISO 16500:2014.

What is the specification of a mill size bale?

To be classed as a Mill Size Bale, a bale of cardboard must weigh no less than 400kg and be sized W 120cm x H 100cm x D 80cm. This uniformity is to ensure that they can be stacked and transported efficiently to the cardboard recycling mills.  As a result of the high pressure exerted by the rams,  bales must always be secured tightly with high quality baling wires and not baling tapes, banding or string. 

How can I make a mill size bale?

Most mill size bales are made from cardboard. The instructions for making a bale are specific to the model of machine you have chosen. The simplified steps to making a bale are:

1. Load the compaction chamber of the baler with waste
2. Initiate the compaction cycle
3. Repeat the steps until the bale is complete
4. Eject the bale onto a pallet ahead of transportation to a recycling facility

Watch an introductory video of a QCR H20 Mill Size Baler below.

Are mill size balers easy to use?

In some ways yes, but in other ways not so much.  Balers are specialised types of waste compaction equipment that must only be operated by trained personnel demonstrating care and attention.  Once you have received appropriate training to become a mill size baler operator, it's important you don't become complacent. Regular refresher training is imperative to ensure you continue to bale waste in an efficient and safe way.

Fundamentals of baling include simple operations such as loading the compaction chamber with waste, to more complex procedures such as ejecting the bale. Sourcing a baler from a supplier that offers free training sessions as part of the package offers additional reassurance. Free baler training & training documentation is offered to all QCR Customers. Refresher training is also available, as are demonstration videos & detailed operator manuals.

Is it better to buy or rent a mill size baler?

Whether it is better to buy or hire a mill size baler depends entirely on your usage, budget and operational needs. Hiring is ideal for growing businesses who are likely to need to upgrade in the near future. Buying is typically more cost-effective in the long run for businesses with stable waste volumes.

Benefits of hire:

• You can easily upgrade to newer models as your waste management needs evolve
• Servicing is often included within the contract when you hire from reputable suppliers
• Avoids a large upfront capital expense

Benefits of purchasing:

• You have complete control of the baler
• You can add it to your asset register

Where should I locate a baler?

Locate your baler in a well-lit spot with a level floor.  Ensure there is sufficient space around it to operate the controls and complete the necessary maintenance tasks. Keep these key factors in mind when choosing the right spot at your premises:

Clearance & Swing: Ensure there is adequate space in front of the baler to safely eject the finished bale onto a pallet.

Access To Control Panel: Users will need easy access to the buttons and switches on the control panel of the machine to intiative the bale-out sequence.

Close to Waste Source: For maximum efficiency, locate your machine as close to the place that generates the waste. This reduces to time it takes to put the waste into the compaction chamber.

How valuable are mill size bales of cardboard?

The value of cardboard, like any commodity will fluctuate over time. However, there are things that your business can do to ensure you get the best return for your mill size bales:

• Sell your bales to a reputable licenced recycling company
• Have your bales collected in large quantities  (full lorry loads often achieve the best returns)
• Produce high-quality bales free from contaminants (for example without food residue)
• Bales stored outside must be palletised and wrapped because moisture content can effect bale value

Mill Size Baler important considerations

Mill Size Balers are subject to the Provision and Use of Work Equipment Regulations 1998 (PUWER).  PUWER requires that all mill size balers installed in workplaces must be suitable for their intended use, maintained in safe working order and inspected regularly. Those responsible for the equipment must ensure:

• SUITABILITY: Check the waste material which you wish to bale is compatible with your machine to prevent damage to the machine itself or injury to those using it.
• SAFETY: Your baler must carry a UKCA or CE mark and be supplied with a declaration of conformity and instructions  written in English.
• BALER MAINTENANCE & SERVICING : Your baler must be regularly inspected, maintained and serviced by a competent person.
• OPERATOR TRAINING: Balers can only be operated by trained personnel. Refresher training should be provided to all users every 3 to 5 years or when bad practice is observed.

Why should I talk to QCR?

QCR offer brand new and refurbished mill size balers for sale with a warranty. QCR also offer both short term and longer-term waste baler rental agreements if your business does not want to purchase a machine outright. This is a great cost-effective option for many UK businesses, especially during periods of rising interest rates and economic uncertainty. The fixed mill size baler hire cost includes machine training, machine delivery, equipment servicing and breakdown cover (parts and labour). It also enables you to upgrade to a larger machine if your waste volumes increase unexpectedly.

QCR will also introduce all our customers to our nationwide network of trusted mill size bale collection companies.

WRITTEN BY NEIL HOLLAND, QCR Recycling Equipment

Article updated: 19/06/2026

Neil is a Mill Size Baler specialist at QCR. Neil recently represented QCR at the Resource & Waste Management (RWM) 2025 held at the NEC in Birmingham. The event was a gathering of leading experts in waste management in the UK. Neil has over 20 years of experience of helping businesses to hire or purchase a mill size baler.