The CAST-IT application engineers have compiled their collective knowledge on the following topics:
Geometric Dimensioning & Tolerancing Casting Quality Tip Series
Case Study 1: Clarifying Datums and Defining Datum Targets
In the Geometric Dimensioning and Tolerancing Casting Quality Tip Series Overview that AMC sent out previously, simple GD&T improvements to help new suppliers achieve first article approvals were outlined. One such opportunity is about clarifying datums and defining datum targets. In the following case study, you will see how simple changes allowed a metalcasting supplier team to avoid dimensional and/or surface finish rejection of their First Article casting.
Simple GD&T Improvements: An Opportunity when Revising Casting Drawings
Geometric Dimensioning & Tolerancing (GD&T) (ASME Y14.5 – 2018) was developed in the United Kingdom in the early 1940s. It originated from the realization that actual parts are three-dimensional and the prior (and still existing) Coordinate Tolerancing System is two-dimensional. GD&T is a system for defining and communicating engineering tolerances and geometrical requirements. Form, fit, and function are at the forefront of this system. As 2D drawings are being updated for other reasons, simple GD&T improvements can be made which will help new suppliers achieve first article approvals.
Impact of Requiring NADCAP Approved Heat Treatment Facilities for Castings
The Defense Logistics Agency (DLA) Aviation Casting and Forging Summit held in September of 2019 and resulting working groups sought to uncover the reasons for sourcing issues, long lead times, and delayed procurements and deliveries of cast and forged components. The Technical and Quality working group discovered a recurring issue caused by technical data package/purchase order requirements for using National Aerospace and Defense Accreditation Program (NADCAP) heat treatment facilities.
In-Process Weld Rework Reduces Cost and Lead Time for Aluminum Castings
In-Process Weld Rework (I-PWR) is an everyday metalcasting industry finishing process that reworks indications of potential non-conformances. This process is often unnecessarily limited which results in an increase in cost and lead times. In 2018, AMC published a Casting Quality Tip on I-PWR in hopes of increasing the understanding and acceptance of this procedure for defense castings. Using the Casting Quality Tip as well as other supporting data, David Weiss, VP of Sales and Engineering at Eck Industries, was able to convince his customer to overturn a blanket specification banning I-PWR.
Internal scrap rate in a metalcaster’s shop is a major concern for casting producers and customers. Pragmatic approval of in-process weld rework, as one of the many normal casting finishing processes, has the potential to drive down the internal scrap rate and the resulting high casting costs and lead times.
Solutions to assist in the FAT process to avoid delays or additional testing costs to best enable a responsive supply chain to support defense procurements, minimize PLT and reduce impacts on stock availability.
The casting process has nearly unlimited flexibility compared to other manufacturing processes and is excellent for optimizing designs based on performance and weight requirements rather than processing limitations.