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Compounders: prepare your troops for battle
Compounders: prepare your troops for battle Imagine sending military troops onto the battlefield with state-of-the-art equipment, but no training on its use.This is the scenario for compounders who have invested in highly automated production lines and staffed them with operators who are expected to learn on the job, argues Adam Dreiblatt of Extrusioneering International, Inc. If the compounder's goal is to produce a certain number of tonnes of pellets per shift, then learning on the job is not a bad approach. However, the goal of compounding is to produce properties, not pellets. Consequently, learning on the job may be very costly in terms of how many pellets are produced as scrap in the process of making properties to customer specifications. Compounding equipment (for example, twin-screw extruders, gravimetric feeders and downstream pelletizing equipment)
has advanced rapidly in recent years, becoming more sophisticated and producing higher throughputs. At the same time, the compounder's customer specifications have become narrower since the equipment is now capable of producing to tighter tolerances. Yet training of production staff has not kept pace with these advances in machinery and controls. To be successful, compounders must proactively assess the training needs of their front-line personnel and provide
Defining quality Modular co-rotating twin-screw extruders have become the most common device for compounding additives, colorants and fillers into thermoplastic materials. These machines impart mechanical energy to melt and mix via the intermeshing screws. The resulting dispersion of particulate fillers and/or distribution of fibres in the polymer(s) are responsible for producing the compound properties for a given formulation. The inherent flexibility built into the design of this equipment allows compounders to produce a wide variety of products on the same machine. It is this same flexibility that makes the operation of such equipment so complex as compared to single-screw extruders. Machine operators should understand, for example, which of the parameters are responsible for influencing compound properties. OEMs provide instruction on how to start and stop the equipment and how to keep it running. They cannot be expected to know which parameters are significant
Twin-screw extruder at Aspen Research.
Plastics Additives & Compounding September/October 2005
them with the tools they need to do the job they are being asked to do. Machine operators, supervisors and process engineers should all share the same vision of compound quality: producing properties versus producing pellets. What is needed is a basic understanding of how the production equipment creates and influences the properties.
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ISSN1464-391X/05 © 2005 Elsevier Ltd.All rights reserved.
Tr a i n i n g for specific compounds. It is the employer's responsibility to educate the operating team as far as process/property relationships. Gravimetric feeders are responsible for producing the desired formulation on starve-fed twin-screws. As the compound properties depend largely on the formulation, accurate and precise feeding of raw materials is critical to achieve the desired properties. If the operating personnel do not know this simple requirement, they cannot appreciate how important feeding is to the compounding process and therefore cannot be expected to respond adequately to problems with feeding of raw materials. Some basic instruction in twin-screw extruder design, process unit operations and troubleshooting are all that is necessary for staff training. When the production team understands and recognizes how the equipment is interacting with the raw materials to produce the compound properties, they can focus on the most critical parameters and are equipped to diagnose processing problems quickly. Knowledge and awareness become the tools that empower operating personnel to improve productivity, compound quality and job satisfaction.
Diagnosing problems In an ideal world, a production line would make a single product only, is configured properly and is in reasonably good mechanical condition. In addition, raw materials are homogenous and identical to every other lot. In this case, the production personnel have little influence in the resulting compound properties. In reality, however, compounders must produce many different products on the same line, requiring reconfiguration and downtime. Raw materials are not all the same and often include recycled resin of varying sources and quality. In most plants, equipment is often neglected until mechanical failures occur. In this real world scenario, operators, supervisors and production engineers are expected to make decisions that directly
impact compound properties and the efficiency with which they are produced (for example, manufacturing costs). If the operating staff is instructed how to identify processing problems, they can react quicker and more intelligently. Look at a simple example: assume that operators spend 2-4 hours per line, per week producing ‘scrap’. With proper training, this non-productive time can be reduced or eliminated. For high-output compounding lines operating at several thousand kilograms per hour, the investment in training (both time and money) can be recovered in less than one month from savings in raw materials and lost production time.
No time for training The dilemma facing compounders has to do with making the time available for their production staff to get training. Management is convinced that they cannot afford the downtime and are reluctant to shut-down the line(s) to accommodate staff training. There are, however, creative methods to make the time available for training.
On-site training using in-house personnel or outside consultants These programs provide the most costeffective means of training, since all team members can be involved and focuses on the employer's installation and products. Scheduling is at the employer's convenience to minimize the impact on production. Training classes can be scheduled during planned shutdowns as well as during off-shifts.
Resources A. Routsis Paulson Training Society of Plastics Engineers (SPE)
Training methods Computer-based interactive training and multimedia training videos. These programs provide training and convenience, since the user can learn at his/her own pace and convenience and include proficiency testing to reinforce concepts. While these programs are excellent for training in single-screw extrusion and injection moulding, the wide variety of compounding applications and twin-screw extruder hardware configurations cannot be accommodated within the scope of these programs. They can provide fundamental concepts of polymer processing and extrusion theory but are limited in their direct application to the employer's installation and products. Off-site training seminars/workshops are offered by academic institutions, industry trade organizations and equipment suppliers.
41
These are usually two to three day programmes and are offered at different locations several times per year. The cost per student can be relatively high since travel expenses to and from the training location are required in addition to the registration fees. As a result, employers only send a select few individuals due to the relatively high cost per student. Specific questions can be addressed relating to the employer's installation and products. Scheduling is at the convenience of the sponsoring organization.
References C. Rauwendaal, K. Kantor, "ComputerBased Interactive Training in Extrusion", Plastics Engineering, June 1998 J. Ogando, "Time to Train? Start with an In-Plant Program", Plastics Technology, January 1996 T. Miller, "Off the Line: Training for Production", Plastics Compounding, March/April 1994 Contact: Adam Dreiblatt Extrusioneering International, Inc. 78 Musiker Avenue Randolph, New Jersey 07869 USA Tel. (973) 895-4088 Fax (973) 895-4391 E-mail: [email protected] Website: www.b4uextrude.com
Plastics Additives & Compounding September/October 2005
has advanced rapidly in recent years, becoming more sophisticated and producing higher throughputs. At the same time, the compounder's customer specifications have become narrower since the equipment is now capable of producing to tighter tolerances. Yet training of production staff has not kept pace with these advances in machinery and controls. To be successful, compounders must proactively assess the training needs of their front-line personnel and provide
Defining quality Modular co-rotating twin-screw extruders have become the most common device for compounding additives, colorants and fillers into thermoplastic materials. These machines impart mechanical energy to melt and mix via the intermeshing screws. The resulting dispersion of particulate fillers and/or distribution of fibres in the polymer(s) are responsible for producing the compound properties for a given formulation. The inherent flexibility built into the design of this equipment allows compounders to produce a wide variety of products on the same machine. It is this same flexibility that makes the operation of such equipment so complex as compared to single-screw extruders. Machine operators should understand, for example, which of the parameters are responsible for influencing compound properties. OEMs provide instruction on how to start and stop the equipment and how to keep it running. They cannot be expected to know which parameters are significant
Twin-screw extruder at Aspen Research.
Plastics Additives & Compounding September/October 2005
them with the tools they need to do the job they are being asked to do. Machine operators, supervisors and process engineers should all share the same vision of compound quality: producing properties versus producing pellets. What is needed is a basic understanding of how the production equipment creates and influences the properties.
40
ISSN1464-391X/05 © 2005 Elsevier Ltd.All rights reserved.
Tr a i n i n g for specific compounds. It is the employer's responsibility to educate the operating team as far as process/property relationships. Gravimetric feeders are responsible for producing the desired formulation on starve-fed twin-screws. As the compound properties depend largely on the formulation, accurate and precise feeding of raw materials is critical to achieve the desired properties. If the operating personnel do not know this simple requirement, they cannot appreciate how important feeding is to the compounding process and therefore cannot be expected to respond adequately to problems with feeding of raw materials. Some basic instruction in twin-screw extruder design, process unit operations and troubleshooting are all that is necessary for staff training. When the production team understands and recognizes how the equipment is interacting with the raw materials to produce the compound properties, they can focus on the most critical parameters and are equipped to diagnose processing problems quickly. Knowledge and awareness become the tools that empower operating personnel to improve productivity, compound quality and job satisfaction.
Diagnosing problems In an ideal world, a production line would make a single product only, is configured properly and is in reasonably good mechanical condition. In addition, raw materials are homogenous and identical to every other lot. In this case, the production personnel have little influence in the resulting compound properties. In reality, however, compounders must produce many different products on the same line, requiring reconfiguration and downtime. Raw materials are not all the same and often include recycled resin of varying sources and quality. In most plants, equipment is often neglected until mechanical failures occur. In this real world scenario, operators, supervisors and production engineers are expected to make decisions that directly
impact compound properties and the efficiency with which they are produced (for example, manufacturing costs). If the operating staff is instructed how to identify processing problems, they can react quicker and more intelligently. Look at a simple example: assume that operators spend 2-4 hours per line, per week producing ‘scrap’. With proper training, this non-productive time can be reduced or eliminated. For high-output compounding lines operating at several thousand kilograms per hour, the investment in training (both time and money) can be recovered in less than one month from savings in raw materials and lost production time.
No time for training The dilemma facing compounders has to do with making the time available for their production staff to get training. Management is convinced that they cannot afford the downtime and are reluctant to shut-down the line(s) to accommodate staff training. There are, however, creative methods to make the time available for training.
On-site training using in-house personnel or outside consultants These programs provide the most costeffective means of training, since all team members can be involved and focuses on the employer's installation and products. Scheduling is at the employer's convenience to minimize the impact on production. Training classes can be scheduled during planned shutdowns as well as during off-shifts.
Resources A. Routsis Paulson Training Society of Plastics Engineers (SPE)
Training methods Computer-based interactive training and multimedia training videos. These programs provide training and convenience, since the user can learn at his/her own pace and convenience and include proficiency testing to reinforce concepts. While these programs are excellent for training in single-screw extrusion and injection moulding, the wide variety of compounding applications and twin-screw extruder hardware configurations cannot be accommodated within the scope of these programs. They can provide fundamental concepts of polymer processing and extrusion theory but are limited in their direct application to the employer's installation and products. Off-site training seminars/workshops are offered by academic institutions, industry trade organizations and equipment suppliers.
41
These are usually two to three day programmes and are offered at different locations several times per year. The cost per student can be relatively high since travel expenses to and from the training location are required in addition to the registration fees. As a result, employers only send a select few individuals due to the relatively high cost per student. Specific questions can be addressed relating to the employer's installation and products. Scheduling is at the convenience of the sponsoring organization.
References C. Rauwendaal, K. Kantor, "ComputerBased Interactive Training in Extrusion", Plastics Engineering, June 1998 J. Ogando, "Time to Train? Start with an In-Plant Program", Plastics Technology, January 1996 T. Miller, "Off the Line: Training for Production", Plastics Compounding, March/April 1994 Contact: Adam Dreiblatt Extrusioneering International, Inc. 78 Musiker Avenue Randolph, New Jersey 07869 USA Tel. (973) 895-4088 Fax (973) 895-4391 E-mail: [email protected] Website: www.b4uextrude.com
Plastics Additives & Compounding September/October 2005