How to choose the best cutting process

By Hypertherm
Posted on 02/02/2017 in SPARK the blog, General

Hypertherm presented a webinar last week titled "Plasma, laser, oxyfuel, waterjet." The webinar explained how each of these four cutting processes work, the advantages and disadvantages of each, and provided guidelines on how to choose the best process for a particular need.

It's difficult to cover a 45 minute webinar in a blog post but here is a high level overview of what was said about each process. Read on, then tell us what you think. Do you agree with our assessment of the various cutting processes?

OXYFUEL

• Relatively low capital equipment costs compared to plasma
• Ability to cut very thick steel
• Can be automated with a CNC to improve repeatability
• Normal to have 2 to 12 torches on one CNC machine
• Hand and machine cutting applications 

The disadvantages of using oxyfuel are that the process is limited to steel and cast iron. You can't cut any other type of metal. It is slow compared to plasma. It causes a large heat affected zone, can cause warpage on material below a half inch in thickness, uses flammable gas, and requires a skilled operator for best quality cuts.

PLASMA

• Lowest operating cost of all the processes
• Can cut any conductive material (e.g. steel, stainless and aluminum)
• Can be highly automated, minimizing need for operator expertise
• Many power level and process gas choices to fine tune quality and productivity needs
• Lower purchase price than laser or waterjet
• Most productive process on steel from a quarter inch to two inches in thickness

Disadvantages are that the upfront purchase cost is higher than oxyfuel, fine feature cut quality is not as precise as laser or waterjet, and that it can only cut metal.  

LASER

• Excellent cut quality through the thickness range
• Highest productivity of all processes on material less than a 1/4 inch; equal to plasma on material up to 3/4 inch
• Better cut quality than plasma on holes with high aspect ratios (i.e., less than a 1:1 diameter to thickness ratio)
• Best productivity and quality for precision sheet metal applications

The main disadvantage of laser is cost. Laser systems require very precise motion capabilities making a laser system expensive to purchase. Maintenance costs are also high, especially for CO2 systems.

  WATERJET

• Excellent edge finish
• Holds a tight tolerance
• No HAZ or mechanical stress
• Can cut just about anything
• Secondary operations (grinding, dross removal) are rarely needed
• Requires few consumables and no gases to monitor or change
• Can use multiple cutting heads on one machine

The disadvantage of waterjet is a slower cut speed compared to other processes. This translates into a high cost per part since it takes longer to cut each part. You also need a steady supply of water and/or abrasive material, and the water can make things a little wet and messy.

If you want to learn more watch the webinar or request our new Guide to Comparative Cutting

Posted in SPARK the blog, General
Tagged with Webinars

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