Quality Waterjet Newsletter 09/12/2006

Cost Analysis of AWJ Cutting

 

Cost analysis of abrasive water jet (AWJ) cutting is an important but complicated task. Several attempts have been made. The latest attempt was from Andersson and Holmqvist(*). The results of their analysis are highlighted here.

 

Their cost analysis is part of a joint effort from a group of 12 members including equipment developers and users, aimed to promote competitive use of waterjet technology. The primary goal is to provide practical guides for optimizing the process. A database containing 500 different combinations of process parameters are being built. The optimum setting is then determined.

 

As an example, the following charts (Left – total cost; Right – running cost) shows the cost distributions based on these assumptions: investment 272,000 , abrasive 0.43 /kg, operator 32.6 /h, working hours per year 3750 h, pump power 37 kW, max pump pressure 410 MPa, utilization 70%, orifice/focusing tube 0.35/1.1 mm, abrasive feeding 625 g/min, 1 cutting head, cutting speed 88 mm/min (cutting 18 mm stainless steel).

 

 

Cost distribution charts (in the paper) for 2 cutting heads as well as 4 cutting heads with smaller nozzles (0.25/0.76 mm) clearly indicate the advantage of multiple heads in reducing the percentage of fixed costs (from about 2/3 to about half of total costs) and thus the cost per unit length. But that comes with more programming and setup time, more scrap material, and reduced flexibility.

 

Abrasive cost is the biggest part of the running cost. Increasing abrasive feeding will increase cutting speed up to a certain point, beyond that the trend will be flatten and even reversed, called saturation curve. The saturation curve depends on a specific machine setup. Higher pressure will increase the cutting speed, but will also increase downtime and maintenance cost. As an example, pressure increase from 350 to 410 MPa will increase cutting speed by 27%, but will triple the cost of spare parts.

 

* Andersson, U. and Holmqvist, G. (2005) Strategies for cost – and time-effective use of abrasive waterjet cutting, in Mohamed Hashish (Ed.), Proceedings of the 2005 WJTA American Waterjet Conference, Houston, Texas, USA, August 21-23, Paper 7B-2.

Beyond High Pressure

Fredrick Equipment, a recognized distributor of high pressure piping components, is proud to offer QualJet/OHP’s line of waterjet pumps and OEM replacement parts along with sapphire and diamond orifice replacements, tools, gauges, and accessories. Call toll-free at 1-888-928-3758.

 

QualJet LLC

Quality Waterjet

Spare Parts Specialist

·  Quality Waterjet Spare Parts

o    Meets/exceeds OEM standards

o    30% longer operation life time than competing products

·  Extensive Parts Coverage for:

o    Flow style, IR Style

o    40K/55K pumps

o    Intensifiers

o    On/off valves

o    Cutting head

o    Swivels

·  OEM Expert

o    20+ year waterjet OEM experience (via OH Precision)

o    Accept small OEM order

 

Durable, Compact 40K PSI Pumps

·  Long operation lifetime

·  Highly cost-effective

·  Light weight and compact

·  Contact us for

o    Custom power end

o    50K psi models

o    Private labeling

o    Custom design

 

 

 

 

 

 

 

 

 

 

QualJet LLC

12819 SE 38th Street, #240

Bellevue, WA 98006

1-866-QUALJET (782-5538)

Fax: 425-378-7776

Email: info@qualjet.com

Website: www.qualjet.com

 

To unsubscribe the newsletter: unsubscribe@qualjet.com

 

For newsletter archive:

www.qualjet.com/Newsletter.htm

 

 

 

 

 

 

 

Copyright ©2005, QualJet LLC