Build-Up an Economical Tool for Machining Operations Cost Estimation

Abstract

Currently, there is a lack of affordable and simple tools for the estimation of these costs, especially for machining operations. This is particularly true for manufacturing SMEs, in which the cost estimation of machined parts is usually performed based only on required material for part production, or involves a time-consuming, non-standardized technical analysis. Therefore, a cost estimation tool was developed, based on the calculated machining times and amount of required material, based on the final drawing of the requested workpiece. The tool was developed primarily for milling machines, considering milling, drilling, and boring/threading operations. Regarding the considered materials, these were primarily aluminum alloys. However, some polymer materials were also considered. The tool first estimates the required time for total part production and then calculates the total cost. The total production time is estimated based on the required machining operations, as well as drawing, programming, and machine setup time. A part complexity level was also introduced, based on the number of details and operations required for each workpiece, which will inflate the estimated times. The estimation tool was tested in a company setting, comparing the estimated operation time values with the real ones, for a wide variety of parts of differing complexity. An average error of 14% for machining operation times was registered, which is quite satisfactory, as this time is the most impactful in terms of machining cost. However, there are still some problems regarding the accuracy in estimating finishing operation times.

Machining: State-of-the-Art 2022

“…The maximum precision achieved, in this case, was 2.52%, which is a very acceptable value for this sector. This value is significantly better than the average estimation accuracy found in the traditional model, which was around 14% [17]. However, these models can be fine-tuned by increasing the volume of data considered for learning, improving the accuracy of the estimate offered by the model.…”

“…The papers included in this Special Issue include two different approaches, with one being a more conventional approach [17], which can be used by any company that regularly uses MS Excel spreadsheets. This model presents different degrees of complexity in machining, distributing these degrees of difficulty by levels in different aspects, and building a model that can be easily adjusted by users, with a view to improving its operational reliability.…”

Selected Aspects of 3D Printing for Emergency Replacement of Structural Elements

“…When milling elements with complex shapes, the greatest efficiency is achieved by using multispindle machining centers and four or five-axis machine tools. The fundamental disadvantages of CNC machines include the high purchase price and high operating costs [5]. However, CNC machines allow cutting components with a more complex geometry than the three-axis milling machines often used.…”

“…The programming multi-axis numerically controlled machines, which are intended in particular for machining elements with complex geometry, require [2,4,5,9,10] In applications such as rapid prototyping of machine components or emergency manufacture of temporarily unavailable spare parts, machining can be replaced by additive 3D printing. By 3D printing, we mean the process of physically producing objects by applying the build material layer by layer and selectively bonding it together.…”