31 Jan 2019

The hard commitment in research, development and improvement of polyurethane mixing technologies led Cannon to  manufacture high quality mixing heads, able to face all customers’ production requirements.

Mixing heads: an overview

In its 50+ years of activity, Cannon Afros built at least 35.000 mixing heads, in various models, sizes and variants, and currently produces more than 1,000 heads per year, the largest part high pressure models.

Cannon mixing heads are divided in 10 families with at least 40 variants, for around 250 different “codes” of our database: a differentiation closely linked to the Cannon will to give life to products which precisely respond to specific market requests.

A new model, in fact, derives either from an intuition of our specialists, commercial or technical, that perceive a new possible application and start working on it (after an initial discreet market survey on its potential), either from the evaluation of a new application, currently in the boiler’s room of some of the major Raw Material Suppliers with whom we usually cooperate for developments.

But, many times, from a client’s need, trying to address a specific problem: if there is a potential market behind a single request, Cannon design a new head.

As mixing heads are one of Cannon best qualifying products, around 50 Cannon people in the world are fully dedicated to them in development, production, maintenance and service of the mixing heads: a dedicated Cannon Afros Technical Office converts into an industrial project a new mixing head model or variant that is, later on, further developed and tested by the R&D Department.

The design is transferred to Cannon Micromec, technological centre for precision machining, which optimises the sequence of mechanical machining operations of each single head’s components. Cannon Micromec uses state-of-art CNC WorkCentres, grinders and lapping machines, as well as a brand new CMMs system for component’s 3D measuring.

Parameters like maintaining the perfect internal and external geometry, as well as the simplification of transfers between different CNC machines, are carefully analysed to optimise machining times, costs and prevent the accumulation of geometrical errors. Easiness of assembling and of maintenance are deeply considered and perfected.

When a prototype is made, it is tested and characterised in the R&D lab with chemicals, and a feedback report is done to apply the necessary improvements. Cannon Micromec corrects what is needed and proceeds then with the final machining and assembling. A very scrupulous series of geometrical controls are run on each head’s element, as well as a complete hydraulic test on pistons and component’s circuits. Then a compliance certificate is issued.

In parallel, samples of the thermally treated elements are sent to an independent Certification Authority to check and guarantee the quality certification that accompanies each lot of heads to Cannon Afros.

If the mixing head is a well-known model, the certified data are controlled and validated, and the head goes to the warehouse, available for Sales. In case of a new model, instead, the head is re-tested in the R&D Lab and its features are fully characterised. When everything fits the expectations and requirements, the head is loaned to an industrial Beta-tester that puts it under stress in real-life conditions, further reporting back results and problems.

This phase is fundamental, since no better judgement can be expressed than that of the industrial end user. At the end of this long industrial testing the head is released for sales and publicised.

Cannon Mixing Head Evolution

Once it was common, for instance for refrigerator cabinets foaming, to mount one head on each polymerisation jig. The head was working for few seconds every 4-5 minutes, at a medium output.

Today, there have been important and fundamental evolutions, both in terms of cycles and of performances: using chemical formulations much faster than before, a refrigerator plant can feature one mixing head travelling across 6-8 foaming fixtures, performing an injection every 20-30 seconds, at a much higher output.

In spite of this, Cannon mixing heads last —as an average —up to eight times longer than thirty years ago.

There has been a great improvement of multiple factors, in the past 10 years: smarter design, more precise machining, stronger metals and new materials, dedicated sealing packs, more efficient surface treatments.

All these steps forward have contributed to the production of components that generate better matching, lower frictions, thus less heat and less wear-and-tear effect. Important benefits widely recognized: Cannon AX22 mixing head has obtained an award from Toyota for its quality, ease of use and reduced operative costs, after having been validated in mass production conditions, while Cannon FPL-SR series has obtained the ATEX Certification, confirming its total reliability against over-heating or accidental production of sparks when using chemical formulations containing Pentane, a potentially explosive hydrocarbon used as physical blowing agent.


The latest generation of heads features so many dedicated and sophisticated solutions that only the manufacturer can assure a perfect refurbishing. The best solution when maintenance is required is send them back to Cannon Afros by the local agencies: in a new technical area dedicated to this purpose, skilled manpower gives back life to old or damaged mixing heads using original spare parts.

Furthermore, to provide fast and less expensive repair service we have organised internal training courses for our Locations, certifying a number of our local technicians to the refurbishing of our most evolved heads. Working locally, in many Countries of the Western and the Eastern markets, our local agencies can supply repaired heads in a very fast way, avoiding expensive and time-taking shipments to Italy.

With a correct maintenance, an incredible number of shots are guaranteed, even if compared with only ten years back. Electronics and modern hydraulics assure faster operating cycles, allowing also to operate only one of the two head’s pistons when a very fast sequence of shots is requested, etc. Every detail counts, in the search for a long lasting head.