Health and Safety on our Rotomoulding Machines Rotomachinery Group Walter BONAZZI POLIVINIL ROTOMACHINERY S.p.A. has been active in the rotational molding industry for more than 40 years producing all kind of rotomolding machines, accessories and ancillary equipments. We have two production sites: the original headquarter in Cerano, in northern Italy, near Milan Malpensa Airport and the factory in Sherbrooke, Québec Canada, founded in 2005. 1
SHUTTLE INDEPENDENT ARMS CARROUSEL BOX-OVENS 360 PRODUCT LINE ROCKING OVENS LAB-MACHINE CUSTOMISED MACHINES SHUTTLE 3 ARMS DOSING UNITS Problems of the safety exists in all the areas of the process. IS ROTATIONAL MOULDING DANGEROUS? Generally on rotomoulding machines we have to consider: - Low speed rotations and carts or turret movements; - Absence of high pressure mechanism; - Burner flame inside a closed chamber; - No dangerous raw materials with low flammability. We may think that a correct burner installation is all we need to ensure the safety of the site and of the people IT'S REALLY LIKE THIS? 2
JUST LOOKING AT: - The weight of the moulds; - Temperature of the oven walls and of the tools; - Need for manual intervention; - High variability of demoulding from part to part; - Loading of the raw material, addictives and use of release agents; - Particular operations (pre-heating, inserts, cleaning and manteinance) IT'S CLEAR THAT WE HAVE HEALTH AND SAFETY ISSUES IN - Machine-related risks; OUR INDUSTRY - Manual operation risks. WHAT CAN WE DO TO MINIMIZE AND TRY TO OBTAIN ZERO RISKS? AS MACHINE MANUFACTURER WE ARE SORRY TO SAY THAT OFTEN SAFETY IS PERCIEVED AS AN OPTION. FEW CUSTOMERS INVEST TIME AND MONEY ON IT: IF APPROACHED SERIOUSLY SAFETY IS A BIG ISSUE. First mistake is the poor attention given to the safety features of the machines (PASSIVE SAFETY) and how the operators will interact with the interface, the moulds and the raw material. COMMON QUESTIONS CAN B - What should I do by-law? - Do I have the installation report for the burner. That's it! - Do I simply rely on manufacturer experience? - Main concerns: - The cost of safety it's too high! - Output slows down! SAFETY COST MUST BE INTENDED - Everything becomes too complicated! - This is not my case! AS A GOOD INVESTMENT - Do I really need all this? GOOD SOLUTIONS ARE NOT EXPENSIVE, EASY AND VERY EFFICIENT 3
There's no vertical harmonized rule EC standard for rotomoulding machines: the manufacuter has to match all the technical requirements according to the solution chosen in each case and related to the specific machine. The goal of the design is a completly safe machine. ACTIVE SAFETY - 1: Barriers, fences and safety ladders On the top of the oven and of the cooling chamber to allow a safe mainteinance. Photocells inter-acting with machine's movement To stop the machine in case of interference of man or objects in dangerous areas for the arms movements, opening/closing of the oven doors). ACTIVE SAFETY - 2: Integrated software to manage dangerous operations The management software forces the operators to follow specific steps using double check button. Easy to understand and to check effectiveness. Movements are blocked if operations are out of safe-protocols. User friendly interface Clear informations, real-time instructions and efficient alarm management. Looking at the datas on the screen will help the operator to follow the protocols. Changing settings is protected by password. 4
ACTIVE SAFETY - 3: Arm Balancing Sudden and unforeseen arm rotation can lead to serious injures. A good balancing (mechanical or via software) can minimize the impact and the risk. Good and efficient thermal insulation of the structure of the oven, Allow to avoid injuries of the operators touching the walls and most of all to reduce the gas consumption and to keep the working ambient cool. ACTIVE SAFETY: A SUBJECT IN CONSTANT EVOLUTION Regulations changes, machines and devices evolves. Active safety must move accordingly. A good solution for a carrousel machine can be a bad solution for a shuttle or a rock and roll machine. Basically, a good cooperation with the customer is required to understand needs and opportunity. You see safety devices we put on all our rotomoulding machines. 5
Read the user manual prescriptions whicharetheresultoftheriskanalysis and where the residual unresolved dangerous situations are well described! FOLLOWING MANUFACTURER'S INSTRUCTIONS -1 Respect max load capacity of the arm The mechanical structures and the safety torque of the braking systems are calculated to avoid dangerous breakages or falls. Periodically check of the alignment of the sprockets and of the primary and secondary rotation is important. Follow the mainteinance schedule Regularly check of screws, bearings, gears and chains it is quite important. Keep clean air inlets, ducts, fans and carts rail to avoid problems during the production process. OPERATOR'S SAFETY To avoid being trapped in the oven, we have put on our machines a system that is composed of a steel wire connected to handles placed inside the cooking chamber. A worker that remained trapped in the oven can pull the handle placed inside the cooking chamber that will immediatly stop the machine. 6
FOLLOWING MANUFACTURER'S INSTRUCTIONS -2 It is very important to do a regularly maintanance of the burner to check the combustion efficiency A good combustion is safe, healthy and convenient. Cleaning the combustion chamber is an operation to consider to do it periodically. Always make sure the arm-mounting flanges are working and fixed properly - Threads - Screw length - Tightening torque TO AVOID PROBLEMS! The active safety of a machine is the result of the risk analysis and structure calculation. The accurate choice of safety devices are not enough. Most of the problems comes from misuse or avoidable errors. COMMON MISTAKES IN DAILY OPERATIONS Having more than 40 years of experience in machines installations, test and training operators of different countries and sectors, with different skills, we can document some common mistakes that impact on safety. On the other side we can even illustrate the best practices seen in more than 1000 installations currently in operation around the world. 7
THE MOST CRITICAL OPERATION: LOADING / UNLOADING Risks are related to human intervention. OPENING AND CLOSING OF THE MOULDS We have personally seen many operators during their free climbing hanging on moulds or even acrobats going on unstable stairs. The risk of serious injuries caused by falls can be easily avoided using mobile platforms. To avoid those risks we suggest our clients to use platforms. When the arm is in position the platform approaches and the operator can work safely, standing on a stable frame. 8
RISK IN REMOVING PARTS We saw operators manually rotate the arm to drop the piece from the mold although it weighs more then 100 kg. The risk of crushing can be avoided using removable hooks. The upper part of the mould is held by the hoist. Then the lower part remains on the arm and the operator let down the piece and removes the inserts in safe. RISK IN REMOVING PARTS OTHER SOLUTIONS: Customised platforms Special equipments and custom configurations can solve particular problems: support frames, automatic opening / closing of the moulds, slides, positioning of the cranes, etc. We suggest you check with the manufacturer to find out the best solution on a case by case basis. 9
RISK WITH RAW MATERIAL HANDLING It's a common practice to load the powder in the mould manually. For heavy weights too! Acrobats may lean out into the mould to better distribute the powder. RISK IN RAW MATERIAL HANDLING Manual operations of handling the powder (opening bags, racking between containers, weighing) that often remain on the floor can create slippery surfaces. THESE RISKS CAN GENERALLY BE AVOIDED USING MATERIAL HANDLINGS AND DOSING SYSTEMS FOR A BETTER WORKING OF THE OPERATORS. 10
RISK IN RAW MATERIAL HANDLING We produce a system to work in safe where the material is stored in a silo and is conveyed into a hopper with a suitable transport system: this allow us to eliminate the risk of leakage of the material and of the handling of the bags. The system allow an automatic reading of the labels for the right quantity and weight. The operator simply directs the pipe into the mould and presses the button for the right distribution of the material: no risk of falling into the mold, right weight dosage and the absence of dust around are the advantages. PRE-HEATING RISK In some cases (complicate shapes with hidden cavities or to obtain different thicknesses) it is required to preheat the mould. The use of direct flames on the mould is the current procedure, even with the mould in rotation! The high risk of burns or shocks with the moving and rotating moulds is evident. Systems are available today for automatic preheating: - Positioning of the mold directly in front of the heating source; - Adjustable deflectors that automatically direct the air in the desired direction; - Innovative air circuit in the head of the arm for the Venturi effect. 11
CONCLUSIONS STAY TUNED FOR THE LATEST TECHNOLOGICAL SOLUTION! For Example: - Why do we use solvent-base release agents? - Water-based release agents doesn't require protections and masks. ALWAYS KEEP SAFETY IN MIND! - QUALITY MOULDS AND QUALITY MACHINES; - LATEST GENERATION OF MOULD CLAMPS; - MACHINES DESIGNED WITH SAFETY; - KEEP IN TOUCH WITH THE MANUFACTURER FOR ANY UPDATE/UPGRADE/MODIFICATION ON THE MACHINE. OBVIOUS: PAY ATTENTION! Forgetting to close a clamp will cause powder leakage from the mould. The powder is taken by the fan and the risk of fire can happen. PE has a low fire index but when the fire is triggered, to put it out can be extremely hard, above all when the structure of the oven is covered with dirty melted polyethilene. THANK YOU FOR YOUR ATTENTION! 12