This course presents various web slitting methods and technical information intended to expand attendee understanding of the slitting process. Details of knife operating forces and their influence on flexible webs, knives and knife holders will be presented. Knife metallurgy and adhesive slitting options will be discussed as well.
New to the program is discussion on how electronic technology has impacted the slitting process. Included is a brief history of electro-mechanical positioning, electronic knife holders and automatic positioning systems with closed loop cut-on-the-fly location change.
Throughout the course, examples of relevant slitting problems and successes will be included. A variety of practical tips and suggested tools will be provided to support existing slitting processes.
This course presents various web slitting methods and technical information intended to expand attendee understanding of the slitting process. The course goal is to have attendees acquire slitting information they can employ to improve their workplace slitting processes. Details of knife operating forces and their influence on flexible webs, knives and knife holders will be presented. Knife metallurgy and adhesive slitting options will be discussed as well. Presentation includes how electronic technology has impacted the slitting process. Included is a brief history of electro-mechanical positioning machinery, electronic knife holders and automatic positioning systems with closed loop cut-on-the-fly location change. Throughout the two-day course, examples of relevant slitting defect causes and remedies will be included. Over 40 practical tips and suggested tools will be provided to support existing slitting processes. Attendee participation is welcome.
COMMON SLITTING METHODS
Featured are Razor, Crush and Shear Slitting web fracturing methods juxtaposed with magnified photographs of various web materials during Lab controlled slitting. These basic descriptions provide an outline for the in-depth slitting analysis to follow. Roll Shear Metal web fracturing, a precise location controlled non-contact knife method, is discussed in some detail as it related to battery foil and stiff plastic converting applications. Presented are an overview of web material properties, (paper, nonwovens, thermoplastic webs, foils, etc.), slitting operating parameters and the dynamic challenges to consider when selecting a slitting method for your operation. Included are some less common but practical slitting methods for material specific web separation applications.
Presented are web deformation comparisons of shear and razor slitting effects. Discussed are non symmetrical razor tip and/or misaligned mounting and blade deflection concerns. Addition discussion includes best materials for razor slitting accentuated with magnified slit edge photos of various web materials. Razor wear and blade oscillation techniques are also discussed. In-Air and Wrapped Web path slitting are compared along with web over-speed options, burst slitting and high roll edge profile (a common process nightmare for thin films). This section also includes a summarization of the benefits and limitations of Razor Slitting.
Key to successful Crush Cutting is to understand the considerable mechanical forces employed to sever a web. Presented are knife holder operation, force analysis, shock loading, knife work hardening and metal fatigue failure. Anvil pitting and scoring surface damage are also discussed. Also covered are anvil roll material options, special web converting applications and heated scoring techniques for dense web materials. Presented are common Crush Cutting problem causes and troubleshooting remedies for process improvement. Summarization will include fifteen operating conclusions and a discussion of Crush Cutting Pros and Cons.
SHEAR SLITTING – A COMPLICATED PROCESS
Presented in detail are twelve (12) of eighteen (18) interrelated operating factors governing successful shear slitting. Pneumatic knife holder function presents a baseline for discussion of the three key shear slitting operation groups; Slitting Geometry, Slitting Dynamic Factors and Shear Knives. Interjected throughout this session is slitter set up defect identification. Geometric Factors discussed include the Cut Point, the Shear Angle, Top and Bottom Knife Run-Out, Knife Overlap and the web path through the Slitting Section; Wrapped or Tangential. Dynamic Factors covered are Knife Holder Integrity and mounting methods, Side Load Force and Knife Friction, Knife Run-Out Force affects, and Knife Over-Speed. Also discussed are Web Tension control, Slit Web Separation and Static Electricity. The remaining six (6) Shear Slitting operating factors are knife related and covered in the Slitting Blades and Knives program section.
ADHESIVE WEB SLITTING
Presented are the pitfalls of both Pressure Sensitive Adhesive slitting and Heat Sensitive Adhesive slitting. Additional information will compare the differences between the World of Adhesive Science and the Manufacturing World most of us must work with. Also discussed are optional techniques to better deal with adhesive web slitting; including knife lubrication, heated and chilled knives, and non-stick surface coatings.
SLITTING BLADES AND KNIVES
This presentation covers Shear and Crush Knives and Razor blades. Discussion includes sizes, shapes and bevels. Shear Slitting Top Knives: Presented are the two more common shear slitting knives in detail. Also provided are knife bevel options, available knife steels and their metallurgy composition. Knife surface finish and the positive effects are presented with a knife metal reference matrix. Shear Slitting Bottom Knives: Carbide and non-carbide metals and various mounting options. Shear Knife Re-Sharpening: This topic covers how shear knives become dull and what negative roll defects can result. This importance of properly re-sharpening knives is discussed. Crush Cutting Knives and Anvils: Common crush knife metals and their metallurgies. Also presented are some special applications utilizing non-standard knives. Razor Blades: Common razor blade metals with a relative performance to cost matrix. Potential for improving blade life with diamond coated razor blades are also presented.
TRIM AND BLEED SLITTING
Discussion includes common trim knife selection and arrangements for Razor, Crush and Shear slitting. Bleed trim slitting is presented for consideration to help minimize High Roll Edge profile with multiple cut film slitting. The importance of proper trim tension control and trim travel path post web fracture will be emphasized in detail. A brief comparison of suction and winding trim removal systems is included with basic do’s and don’ts. Common trim removal problems are also presented.
PNEUMATIC AND ELECTRONIC SHEAR KNIFE HOLDERS
A comparison of traditional pneumatic knife holder operation to newer electronic knife holder performance lays the ground work for better understanding of how these related operating technologies have benefitted from the capabilities of slitter automatic positioning systems. Discussion includes calibration techniques for a knife holder’s critical Overlap and Side Load Force settings. Also presented are servo-motor holder response times, location accuracy potential from encoders, ball screws and load cells when employed in the slitting and positioning processes.
MANUAL AND AUTOMATIC POSITIONING SYSTEMS
This presentation begins with a brief history of papermaking and how the increasing demand for print and writing paper through the ages helped create our paper and converting industries. From there we’ll follow how technical advancements have positively impacted the slitting process with increased throughput, higher roll quality, improved efficiency, reduced scrap and better operating safety. Discussion includes fundamentals and details of Dual Shaft Shear slitting systems and improvements made from the 1800’s.Also shown is how automatic slitter positioning system technologies dramatically reduce set up time by simultaneously changing all holder locations. Additionally, discussion includes how slitters can be commanded to react to signals from other winding system sensors; such as web vision cameras, edge guiding devices, load cells, drives systems and other equipment as needed. We’ll also look at the potential of real time data gathering from multiple on-line sensors to quantify a finished roll’s quality.
SLITTING PRACTICAL MATTERS
This final course section presents recommended policies and procedures to help gain better control of the slitting process. Over 40 potentially useful ideas, tools and or procedures are presented. Discussion also includes Slitting Dust; quantify Shear Slitting set up; measuring Shear Angle and Radial Run-Out, setting Side Load Force and Top Knife Overlap. Additional subjects include knife sharpness checks, knife holder integrity and knife care.Also presented are various slitting defect causes with techniques and/or tools to mitigate impact on the production process.