Effect of Underlay Stiffness on Cutting Profile of Polycarbonate Sheet during Wedge Indentation Process

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A wedge cutting method with a center-beveled blade is widely used for cutting various laminated sheets such as printed labels, optical adhesive sheets, and multi-functional adhesive films for electronic equipment. In general, the laminated sheet has a pressure-sensitive adhesive (PSA) in the intermediate layer. When a wedge blade indents to a laminated sheet, trouble occasionally occurs because of the blade getting with PSA and PSA flowing out from the cut surfaces. This problem has not been sufficiently clarified. Several reports exist about the cutting behavior of a laminated structure composed of paperboard and monolayer viscoelastic material; however, almost no reports exist on the cutting behavior of laminated sheets with PSA. Therefore, this paper aims to elucidate the effect of a wedge shape on the cutting behavior of a laminated sheet with PSA and polyethylene terephthalate (PET). The cutting characteristics of a 0.1 mm PSA layer sandwiched by upper and lower PET films of 0.1 mm were experimentally and numerically investigated. The cutting load response was measured using indentation depth when the apex angle of the wedge blade was changed. A CCD camera was also installed for investigating the side-view deformation of the laminated sheet. When an apex angle from 16° to 60° was chosen, the cutting force and the bent-up angle of the laminated sheet linearly increased with respect to the apex angle for certain shallow indentation depths. The experimental results showed that the cutting load response and deformed state of the laminated sheet were similar to those of the visco-elastic model based on finite element method (FEM) simulation. In addition, the peak force and the bent-up angle considerably increased with the apex angle, especially when a large apex angle was chosen The fact that the apex angle influenced the cutting characteristics of the laminated sheet during wedge indentation was clarified.

Section: Cutting Load Characteristicsmentioning

confidence: 83%

Section: Introductionmentioning

confidence: 99%

Wedge indentation characteristics of pressure-sensitive adhesives sandwiched by polyethylene terephthalate films

Kaneko

Nagasawa²

2020

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“…Chaijit et al (2008) discussed the combination performance of underlay stiffness with respect to cutting characteristics of thin sheet against a wedge indentation, when changing the combination stiffness and yielding strength of the underlay. A combination of the edge shape of blade and the stiffness of underlay affected the load response and sheared profile of workpiece (Mitsomwang et al, 2012). Murayama et al (2003Murayama et al ( , 2004 have reported the cutting mechanism of a 42° wedge indentation into a 4mm thickness aluminum sheet using a trapezoidal cutting blade imitated as a crushed tip.…”

Section: Introductionmentioning

confidence: 99%

Effect of anvil profile on cutting characteristics of polystyrene bar subjected to wedge indentation

Ruchirabha

Nagasawa

2020

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This research was aiming to investigate cutting characteristics of Polystyrene (PS) 3 mm square bars subjected to indentation of a center bevel (blade angle of 42°) steel blade and stacked on an AL anvil (underlay). To reveal the effect of contact width of workpiece against the anvil on the sheared edge profile of workpiece, the contact width was varied from 1 mm to 40 mm during the cutting test. In this process, the cutting load response was investigated and the sheared edge profile of workpiece was observed by a microscope. To discuss the effect of the anvil width on the deformation behavior of workpiece, a finite element method (FEM) analysis with elastoplastic plain strain model was developed using a crack generation rule. Through the experiment and FEM analysis, a proportion of wedge penetration flow and crack propagation of sheared workpiece was revealed with the contact width. The peak maximum cutting force, pre-crack position and the breaking position were characterized with the contact width. When the contact width was two times or much larger than the thickness of workpiece, the wedge penetration flow form was remarkably appeared, while the crack propagation based smooth flat form was appeared when the contact width was narrower than the thickness of workpiece. A bentdown or bent-up deformation of workpiece varied with the contact width and its sign change occurred when the contact width was about two times of the thickness of workpiece. When choosing the narrower contact width than the thickness of workpiece, an asymmetric crack propagation occurred due to the misalignment of blade position against the left and right side edges of anvil.

“…Before discussing the PSA sandwiched sheet cutting, it is necessary to reveal the deformation characteristics of a single bulk PSA sheet which is subjected to a wedge indentation. As for the solid sheet materials, there are several papers on the cutting behavior of laminated structure (Chaijit et al, 2008), resin material (Mitsomwang et al, 2012, Nagasawa et al, 2010a, 2010b and viscoelastic material (Boisly et al, 2016, McCarth et al, 2010. In addition, several numerical studies had been reported to predict the time-dependent deformation characteristics of viscoelastic materials (Kucuk et al, 2013, Okazawa et al, 2007.However, there are not almost research papers on the cutting characteristics and compressive flow behavior of the PSA sheet.…”

mentioning

confidence: 99%

Estimation of viscoelastic resistance and subduction profile of acrylic based pressure sensitive adhesive sheet subjected to wedge indentation

Kaneko

Nagasawa

2019

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This paper aims to estimate the indentation resistance and deformation shape of a 0.5mm thickness acrylic Pressure Sensitive Adhesive (PSA) sheet subjected to a wedge indentation. As for the effect of apex angle of a wedge blade on the cutting characteristics of the PSA sheet, a 60° wedge blade was mainly investigated through experiments and numerical simulations, while the wedge angles of 42, 16° were discussed with respect to the subduction profile of wedged surface. For the sake of development of PSA deformation model, the Prony series based viscoelastic properties were determined by the shear stress relaxation test. Also, the equivalent Young's modulus was estimated by comparing with an out-of-plane compressive experiment and a Finite Element Method (FEM) based compressive simulation. Through the experimental wedge indentation using the 60° wedge blade, three stages of cutting load response were detected: (1) an exponential response, (2) an extremely increasing response based on the saturated inclined angle of subduction zone, and (3) a saturated gradient for the final stage. Furthermore, it was clarified that the proposed FEM model of viscoelastic-deformable sheet subjected to the 60° wedge indentation was applicable for simulating the cutting deformation for the early stage less than 60% of the thickness. The simulated inclined angle of subduction zone tended to be linearly increased with the indentation depth up to a certain extent, whereas the experimental inclined angle saturated to a constant for the indentation depth larger than 70% of the thickness. One of the reasons why the experimental cutting force was higher than the simulated result was explained as the wetting spreading effect due to the yield flow of PSA sheet. In the latter stage of indentation, the correlation between the mismatching of cutting line force and the mismatching of inclined angle of subduction zone was revealed.temperature of the substrate. The PSA can be classified from the aspects of the physical and chemical composition, i.e. the main elastomer used in the adhesive formulation is such as acrylic, styrenic block copolymers, natural rubber and silicone. The acrylic based PSA is acrylic esters that is yield soft and tacky polymers having the low glass transition temperature. Generalized acrylic PSAs are composed of 50~98 % main monomer, 10~40 % modifying monomer, and 0.5~20 % monomer with functional groups (Satas, 1999). They have many applications spread in various fields, from a specific to common usage. They are applied to self-adhesive labels, protective films, sign and marking films.When the wedge cutting is applied to a laminated sheet which has a PSA in the intermediate layer, various troubles sometimes occur. As for real jamming, there are several reasons by being wet on the blade, detaching/peeling of the end of sheared section and flowing out from the sheared section. The jamming phenomena are not revealed sufficiently, while many actual troubles are empirically taken by the hand operation of experts. In order to predi...