A frugal CNC Oxyfuel Cutter

Cad model of the CNC oxyfuel cutter

Project Overview

This project presents a low-cost CNC oxyfuel cutter designed specifically for metal fabrication microenterprises in Oman. These small workshops often build structural and non-structural items such as gates, staircases, warehouses, and furniture — all requiring the cutting of thick steel plates (3–50+ mm).

Despite the efficiency of automated cutting, CNC machines remain inaccessible to these workshops due to high cost, limited space, and lack of local availability.

Understanding User Needs

A field study was conducted in the industrial cluster of Wadi Kabir Sanaya, Muscat. Most workshops are open-air, compact (15–20 m²), and operated by 2–3 migrant workers from South Asia. Key insights from interviews and observations include:

No existing use of CNC or digital fabrication tools
Frequent use of handheld oxyfuel torches
Cutting done on full or scrap sheets, often outside due to their weight
Strong preference for compact, affordable, and stowable machines
Limited access to electronics or precision components locally

Interviewing owners and workers from various steel fabrication microenterprises in Oman.

Design Decisions

Why Oxyfuel Cutting?

Among various fabrication processes, gas cutting was selected for automation due to:

High repetition of cutting tasks
Time-consuming and hazardous manual cutting
Poor cut quality requiring extensive post-processing

Frugal, Participatory Design

The machine was designed with end users using a co-design approach whereby the prototype was fabricated within one of the workshops. Workers participated in:

Suggesting fabrication methods
Design improvements
Solving design challenges during assembly for example by co-designing by prptotyping some of the complex sub-assemblies like the Z-axis
Assembling the machine frame in the workshop

Local Constraints and Adaptations

The machine was built from easily available surplus workshop materials (e.g., 2” square steel tubing)
Simple linear guides using locally available roller bearings
No reliance on imported machine torches — compatible with users’ own handheld torches
Fabrication aided by paper templates for marking and drillingpp

// put picture of the excel sheet of available local material, next to it show the basic hand torch

Materials like aluminum and precision linear rails were unavailable or too expensive
No access to standard machine parts (e.g., M3 screws), so designs were adapted
CAD development followed field sketches and rough calculations

//put picture of the workshop setting, and a drilling picture to show jibg

Key Features

Affordable: Target price $500–800 (small shops), up to $3000 (larger shops)
Compact: Easily stowable when not in use
Safe & Efficient: Reduces risk, labor, and post-processing
User-Centric: Designed and built with the microenterprise workers taking local materials and capabilities into account

Prototyping

Gallery

References

2023

Exploring the Potential of Open Source Machine Tools for Sustainable Industrial Development in Low Resource Contexts - A Case Study of Migrant-Run Microenterprises in Oman

Mohammed Omer, Melina Kaiser, Tobias Redlich, and 1 more author

In Manufacturing Driving Circular Economy, 2023

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In low resource contexts, access to technologies is limited. Most firms in developing countries are still using analog technologies and have not attained the industrial maturity required to harness the benefits of industry 4.0, which include increased productivity and a reduced environmental impact of the manufacturing sector. This further exacerbates the unequal wealth distribution pervasive in today’s globalized world. With the democratization of the internet and increasing accessibility to microcontrollers and automation technology, the last decade has seen the rise of open source machine tools (OSMT) such as CNC mills and 3D printers. By facilitating sustainable and inclusive production capacity building, OSMT are a key technology driver that can enable developing countries to leapfrog their industries. However, their potential for cost effective and low-threshold production capacity building in developing countries has been hitherto underexplored. This paper reports the findings of a pilot study in Oman with ten migrant-run microenterprises in the carpentry and steel fabrication industries. Semi-structured interviews and field observations were carried out to gain an understanding of the technology needs and readiness levels of the target group. The study identifies and discusses the challenges that could hinder the implementation of OSMT in a resource constrained context, which include insufficient technological and digital literacy, a lack of formal education, and risk adversity. Based on this, the paper proposes solutions to foster OSMT adoption.

2022

Democratizing Manufacturing – Conceptualizing the Potential of Open Source Machine Tools as Drivers of Sustainable Industrial Development in Resource Constrained Contexts

Mohammed Omer, Melina Kaiser, Manuel Moritz, and 3 more authors

2022

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Similar to open source software, the open source hardware (OSHW) movement is seen as a technology driver which can enable developing economies to leapfrog their industries. While machine tools are a subset of OSHW, they have received relatively little academic attention compared to electronic OSHW. This study applies an explorative research approach and analyses open source designs for machine tools freely available on the internet. By coining, the term open source machine tools (OSMT), it determines their applicability in low resource contexts and identifies the potential of OSMTs in democratizing manufacturing technologies. OSMTs thereby encourage diversification, entrepreneurship, and inclusive industrial development, thus contributing to the implementation of Sustainable Development Goal no. 8 which aims to promote inclusive and sustainable economic growth. Specific areas for OSMT application in low-resource contexts and factors and barriers affecting their success are singled out.