Rapid tooling using friction stir welding and machining

Purpose This paper aims to present a friction stir molding (FSM) method for the rapid manufacturing of metal tooling. The method uses additive and subtractive techniques to sequentially friction stir bond and then mill slabs of metal. Mold tooling is grown in a bottom-up fashion, overcoming machining accessibility problems typically associated with deep cavity tooling. Design/methodology/approach To test the feasibility of FSM in building functional molds, a layer addition procedure that combines friction stir spot welding (FSSW) with an initial glue application and clamping for slabs of AA6061-T651 was investigated. Additionally, FSSW parameters and the mechanical behavior of test mold materials, including shear strength and hardness, were studied. Further, scanning electron microscopy (SEM)/elemental map analysis (EDS) of the spot weld zones was carried out to understand the effect of FSSW on the glue materials and to study potential mixing of glue with the plate materials in the welded zone. Findings The results indicate that FSM provides good layer stacking without gaps when slabs are pre-processed through sand blasting, moistening, uniform clamping and FSSW using a tapered pin tool. The tensile shear strength results revealed that the welded spots were able to withstand cutting forces during machining stages; however, FSSW was found to cause hardness reduction among spot zones because of over-aging. The SEM/EDS results showed that glue was not mixed with slab materials in spot zones. The proposed process was able to build a test tooling sample successfully using AA6061-T651 plates welded and machined on a three-axis computer numerical control (CNC) mill. Originality/value The proposed FSM process is a new process presented by the authors, developed for the rapid manufacturing of metal tooling. The method uses additive and subtractive techniques to sequentially friction stir bond and then mill slabs of metal. The use of FSSW process for materials addition is an original contribution that enables automatic process planning for this new process.

Sheet metal forming using FDM rapid prototype tool

Purpose – The purpose of this paper is to investigate usage of fused deposition modeling (FDM)-based sheet metal tooling for small lot productions as a real case. FDM-based sheet metal tooling was used for stamping prototype parts for two different materials to evaluate dimensional conformance. Design/methodology/approach – The experimental process of data capture used the following steps: sheet metal parts were stamped and optically scanned at every 10th interval for both DC04 and S355MC material. FDM-based upper and lower dies were optically scanned at 1st, 51st and 101st intervals. Dimensional conformance analyses were carried out by using scanned data to evaluate the behavior of FDM dies against DC04 and S355MC materials in terms of geometric deviation. Findings – Satisfactory results were obtained for DC04 material by using FDM-based tooling, and overall deviation was at an acceptable level in terms of production tolerance. S355MC material is harder than DC04 and results were not convenient in terms of tolerance range. Geometric deviation of FDM dies was slightly increased and after the 50th part, increased drastically due to squeezing of FDM layers. Experiments showed that this method can be used for DC04 material and up to 100 parts can be stamped within the tolerance range. Using FDM-based sheet metal tooling, product development phase can be shortened in terms of leading time. Originality/value – This paper presents a study to create an alternative tooling method to shorten product cycle and product development phase by integrating rapid tooling methods to low-volume production.

Tow Mechanics: A Contact Mechanics Approach of Friction in Fibrous Tows during Forming

Composites forming processes involve mechanical interactions on the ply, tow, and filament level. The deformations that occur during forming processes are governed by friction between tows and tooling material on the mesoscopic level and consequently between filaments within the tows on the microscopic level. A thorough understanding of the frictional properties of individual filaments is essential to understand and to predict the macroscopic deformations of a fabric during forming. This paper provides a global description of the experimental and modelling approaches to explain the contact friction between fibrous tows and metal tooling material, focusing on contact mechanics at the tow and filament scale.

Experiments on Olive Husk-Addition to Masonry Clay Bricks on their Mechanical Properties, and their Application and Manufacturability as an Insulating Material

Clay has been used in Jordan as a building material for decades. This paper investigates the effects of adding olive husk –another locally available solid waste material- on the mechanical properties of the clay composite, and its modification of the ductility and thermal resistance for use as an insulating material. Laminated Metal Tooling (LMT) process will be used to manufacture the dies required to cast and dry the test specimens. A discussion will also be included regarding the eligibility of the material for the use as a low-cost, high efficiency insulating material depending on the manufacturability of husk-enhanced clay sheets.