Technical Minutes

Jim Throne, Sherwood Technologies, Dunedin, Florida Introduction Often, when a sheet of plastic is heated prior to forming it into a part, there are planes of heaters above and below the sheet. The heaters often have many segments, with each segment temperature controllable. As a result, the energy input to the sheet can be “shaped” […]

Continue reading about An Improved Algorithm for Determining Energy Interchange Between Heaters and Sheet in Thermoforming

Jim Throne on November 16th, 2006

Jim Throne, Sherwood Technologies, Inc., Dunedin Florida 34698 Copyright 2006 Introduction In Part 1, we focused on simple experiments to determine the interaction between a 3-inch hemispherical wood plug and a 0.020-inch thick natural rubber sheet. We examined the transfer of grease dots from the wood plug to the rubber sheet. In addition, we noted […]

Continue reading about Does the Thermoforming Sheet Slide on the Plug? – Part 3

Jim Throne on November 6th, 2006

Jim Throne, Sherwood Technologies, Inc., Dunedin Florida 34698 Copyright 2006 Introduction In Part 1, we focused on simple experiments to determine the interaction between a 3-inch hemispherical wood plug and a 0.020-inch thick natural rubber sheet. We examined the transfer of grease dots from the wood plug to the rubber sheet. In addition, we noted […]

Continue reading about Does the Thermoforming Sheet Slide on the Plug? – Part 4

Jim Throne on November 2nd, 2006

Jim Throne, Sherwood Technologies, Inc., Dunedin Florida 34698 Copyright 2006 Introduction In Part 1, we focused on simple experiments to determine the interaction between a 3-inch hemispherical wood plug and a 0.020-inch thick natural rubber sheet. We examined the transfer of grease dots from the wood plug to the rubber sheet. In addition, we noted […]

Continue reading about Does the Thermoforming Sheet Slide on the Plug? – Part 2

Jim Throne on October 20th, 2006

Jim Throne, Sherwood Technologies, Inc., Dunedin Florida 34698 Copyright 2006 Introduction Nearly all thermoforming processes employ mechanical assists to differentially stretch the heated sheet prior to contact with the mold surface. The mechanical assist is usually referred to as a plug. It has always been assumed that, as the plug enters the hot sheet, the […]

Continue reading about Does the Thermoforming Sheet Slide on the Plug? – Part 1

Jim Throne on October 4th, 2006

Individual Power Points Power Point of Thermoforming Conference 09-06 Title Page Power Point of Thermoforming Conference 09-06 Heating Page Power Point of Thermoforming Conference 09-06 Stretching Page Power Point of Thermoforming Conference 09-06 Trimming Page One ZIP File ZIP File of Four Power Points of Thermoforming Conference 09-06

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Jim Throne on January 16th, 2003

James L. Throne, Sherwood Technologies, Dunedin Florida 34698 Peter J. Mooney, Plastics Custom Research Services, Advance North Carolina 27006 Abstract Thermoforming is the process of heating and shaping plastic sheet into rigid containers, components of final assemblies, and stand-alone end-use parts. The value of all thermoformed parts produced in North America in 2003 exceeded US$10 […]

Continue reading about Thermoforming: Growth And Evolution II

Jim Throne on November 21st, 2002

James L. Throne, Sherwood Technologies, Inc., Dunedin Florida 34698 Peter J. Mooney, Plastics Custom Research Services, Advance North Carolina 27006 Abstract Thermoforming is the process of heating and shaping plastic sheet into rigid containers, components of final assemblies, and stand-alone end-use parts. The value of all thermoformed parts produced in North America in 2003 exceeded […]

Continue reading about Thermoforming: Growth And Evolution I

Background In Part 1 of this treatise, I discussed some of the background thinking on solids sliding on polymeric surfaces. I identified friction as part of the tribological triumvirate of friction, lubrication, and wear. I reviewed the various methods for measuring frictional coefficients and concluded that for plug-polymer sheet interaction, the extent of sliding is […]

Continue reading about Sliding Contact Between Solid or Semi-solid Polymer and Non-polymer – Part 3

Background In Part 1, I presented experimental data on sliding of E&C syntactic foam on 0.120-inch black general-purpose polystyrene sheet at a temperature substantially above its glass transition temperature. But I did not address the question: What is sliding against what? In this part, I try to identify the conditions under which the plastic sheet […]

Continue reading about Sliding Contact Between Solid or Semi-solid Polymer and Non-polymer – Part 2