Monterrey Campus

Manufacturing Processes Laboratory 1/12

School of EngineeringMechanical Engineering DepartmentManufacturing Processes Laboratory

Practice 5: Water jet cutting

THEORETICAL FRAMEWORKThe technology of water jet cutting consist in the shoot of a jet of water at high pressure, through a nozzle which moves over the work area. Such a nozzle, called cutting head is mounted on a structure that allows it to move in 3 axes (X, Y, and Z) and even rotate or tilt, depending on the machine model with which they work. These movements are controlled by a computerized feedback system, which provides high accuracy and repeatability of the cuts.

It can be cut virtually any material with the ability of the machine to mix a type of abrasive grit with water, which can be cut high strength materials or thickness. If you are working with soft materials, cuts can be made only with water.

Figure 1. Water jet cutting machine (3 axes) [available in Tecnológico de Monterrey].

Monterrey Campus

Manufacturing Processes Laboratory 2/12

Among the applications of this technology are found the cutting of metals, polymers, wood, stone, textiles and even food.

PROCESS PARAMETERS

Water pressure: 55,000 PSI Air pressure (abrasive): 20-45 PSI Water consumption: 0.85 Gal/min Shutter speed: 1 Km/s approx. (3 veces la velocidad del sonido) Maximum travel speed: 150 in/min

ADVANTAGES

Machining of flat and three-dimensional pieces. Cutting slots of high quality. Cutting edges clean and without burrs. The burr produced is minimal. High feed rates. Absence of high cutting temperatures. The piece remains unchanged in its

properties. No heat is produced. Soft materials do not strain with the cut. Less loss of material in the slots. It can be cut Steel thicknesses up to 5 inches. It is an environmentally safe manufacturing process.

WATERJET CUTTING HEAD STRUCTURE

Jewel orifice: The jewel orifice focuses the water stream. This orifice is made on diamond, ruby or sapphire. The opening ranging in size from about 0.005 to 0.016 inch diameter.Mixing/Focusing Tube: Is where the abrasive mixes with the higher-pressure water before striking the material1.Water inlet/high-pressure water: Water supply for the cut and the pressure reaches from 50,000 to 90, 000 PSI through the use of a specially designed intensifier.Guard: Protection to the mixing tube and reduce the amount of water that is deflected during a cut.Abrasive Hose supply: Transports the abrasive sand (garnet) used for the cuts.

1 http://www.cimindustry.com/article/formingfabricating/looking-inside-the-waterjet-cutting-head

Monterrey Campus

Manufacturing Processes Laboratory 3/12

Figure 2. .Parts of a water jet cutter (Image courtesy of MultiCam Canada2).

HYDRAULIC CIRCUIT

Process:

1. The electric motor energizes the hydraulic pump.2. The hydraulic pump takes the oil from the reserve and pressurizes until 3000 PSI.3. The pressurized oil is sent to the valves where the pressure is increased and

later is sent to the pistons.4. The intensifier is a reciprocal pump, in which the piston expands and contracts, giving

water to high pressure in one side of the intensifier while in the other is water to low pressure.

5. Later the hydraulic oil is cooled in the return from the reserve.

WATER CIRCUIT

Consist on water filters at the entrance, pumps for increase the pressure, intensifier and impact attenuator.

2 http://www.cimindustry.com/article/formingfabricating/looking-inside-the-waterjet-cutting-head

Monterrey Campus

Manufacturing Processes Laboratory 4/12

Process:

1. Ordinary water is filtered using a filtering cartridge.2. The wáter travels to the pump that rises the pressure until 90 PSI approximately and it

sent to the intensifier3. The water goes through the impact attenuator for guarantee the pressure of the water

stream comes out without fluctuations.4. The water is shot through the nozzle.

Figure 3. Diagram of the hydraulic circuit.

Monterrey Campus

Manufacturing Processes Laboratory 5/12

OBJETIVES1) The student will understand the specific safety standards applicable to practice.2) Students will learn about the performance of the waterjet machine and its operations.3) The student will execute cuts in some materials at different advance cut velocities with the support of the qualified personal.4) The student will estimate the dimensional precision of the cuts and will compare the finished of the cuts in the different materials according to the velocity in the advance used.

SAFETYFor use the instruments and do the measures is required that the following precautions are taken:

WARNING! REASONDo not apply excessive force in the measure tools This can make a permanent deformation in the tool.

Do not take out any measure tool from the metrology area.This area has controlled temperature and taking out

the instrument from this environment can make wrong measures because of thermal dilatation.

Clean the piece and the contact area between the piece and the measure tool. Get a right measure.

Keep always a clean measure tool. Do not get the tool out of calibration and then do not lose precision.

For use of the tool machines is required to attend the following cares.

WARNING! REASONAlways wear safety glasses when handling any machine.

The risk of jumping chips and cause damage in eyes is high.

Never wear loose hair, loose clothing, rings and watches to handle any type of machinery.

The turning elements of the machinery can catch clothes or jewelry causing great physical damage.

Keep the floor clean around the machinery without chips, oil and cutting fluid.

Is easy to slip or stumble causing serious accidents.

Monterrey Campus

Manufacturing Processes Laboratory 6/12

During the operation of the tool-machines should always follow the procedures listed below:

Attention! Reason

Never attempt to operate a tool machine if is not familiar with it.

The risk of damage to your person and / or the machine is high.

Do not lean over the machines. Always stay upright, making sure your face and eyes stay away from chips flying away.

The rotating elements of the machine can catch your clothing or jewelry and cause great physical damage. Furthermore, the risk of eye damage, by jumping chip, is high and very real.

Never attempt to assemble, measure or adjust the workpiece until the machine has stopped completely.

The inertia of the machines is large and can dislocate an articulation, damage the skin or even boot a finger.

At all times keep hands, brushes and rags away from moving parts of the machine tool.

Before making a cut, make sure the workpiece and the tool are mounted correctly and secured tightly.

A piece or a tool that thrown out of the machine is a highly dangerous projectile.

All work performed on a machine tool must be firmly attached either to press, staples or other fastening device; never try to hold the pieces with your hands.

Never leave torque wrenches or other accessories in a mechanism that will turn.

Always use a brush to remove chips, never use your hands to do this task.

Chip can be sharp or hot.

Never attempt to vary the speed of a machine when it is running

Disengage moving transmissions damage the mechanism when are transmissions without synchronization.

You should never hit the tables of machines. The table is the “soul” of the machine, hit or scratch it decrease life and diminish the accuracy.The chip must be retired with a brush from the

table to the end of every process.

Monterrey Campus

Manufacturing Processes Laboratory 7/12

MATERIAL, TOOLING AND EQUIPMENT1) Material

a) Plates and bars of various materials.

2) Toolsa) Vernier.

3) Equipment and machinerya) Water jet cutting machine.b) Stereoscope.

4) Safety equipmenta) Safety glasses.

PROCEDURE1) Print and read all the practice before to go to the laboratory. Prepare the Pre-report.2) Be on time for the practice, wear comfortable clothes, close and strong shoes, without jewelry nor chains; the pre-report must be complete and the report printed and stapled (pages 8 to 12)3) The instructor will apply a test at the beginning of the session, which will assess their understanding of the theoretical mark and also will be used as a list of attendance.4) The instructor will explain the principles of operation of the machine of cut by water beam5) With help of the personal of the laboratory will be performed various cuts is some materials varying the velocity of advance.6) Finally, the alumni will analyze the finish of the cut in the pieces.

Practice 7 Water jet cutting

Student ID

GroupInstructor

Monterrey Campus

Manufacturing Processes Laboratory 8/12

Engineering schoolDepartment of Mechanical

EngineeringFabrication Processes

Laboratory

PRACTICE PRE REPORT

Receipt Acknowledgment

With my signature below, I accept standards and mandatory safety procedures for Practice 7: water jet cutting in the Laboratory of Manufacturing Processes.

Name: ID: Curse key: Group: Signature: Date:

1) Describe the following components of the machine of water jet cutting: pumping system and cutting head. Describa los siguientes componentes de la máquina de corte por chorro de agua: sistema de bombeo, cabezal de corte.

Bibliographic references consulted:

Bibliographic references consulted:

Monterrey Campus

Manufacturing Processes Laboratory 9/12

2) Mention 5 applications of the wáter jet cutting (and products). Mencione 5 aplicaciones del corte por chorro de agua (productos).

Practice 6 Water jet cutting

StudentID

GroupInstructor

Manufacturing Processes Laboratory 10/12

Monterrey Campus

School EngineeringDepartment of Mechanical

EngineeringLaboratory of

Manufacturing Processes

PRACTICE REPORT1) What ratio has the cutting speed of the machine with finishing parts made?

2) Explain the ratio between the cutting speed, the strength of the material to be cut and the thickness for a process of water jet cutting.

Manufacturing Processes Laboratory 11/12

Monterrey Campus

3) In the steel piece do the following measurements (twice each), top and bottom. Is there a variation in size?

4) Explain why the variation in the measurements made previously.

Monterrey Campus

Manufacturing Processes Laboratory 12/12

5) What material had scratched the surface more than the others? Why?

6) What are the advantages of water jet cutting over conventional machining processes (milling machines, lathes)?

DELIVERY OF THE REPORT AND THE PRE-REPORT OF THE PRACTICEMake sure your pre-report and report have all data of the identification box and you have answered all requested items before delivery to the instructor. Then, go to the store to deliver the materials, tools and accessories, and make sure to leave the work area clean and in order, before retiring.