Mastering the Art of Waterjet Cutting: Quality Grades and Factors You Should Know

Delivering an impeccably cut part is every manufacturer’s goal in industrial cutting processes. A smooth cut not only enhances the visual charm of the piece, but it also negates the necessity for follow-up finishing procedures. 

Our focus here is waterjet cutting-edge quality. Understanding this critical aspect can aid manufacturers in comparing waterjet cutting to other cutting methods. Moreover, it can pave the way for improved production outcomes.

Dive into this comprehensive guide where we break down the essence of edge quality in waterjet cutting and provide you with techniques for achieving top-notch cutting results.

Demystifying Waterjet Cut Quality

The quality of a waterjet cut can be classified into various grades, essentially determining the preciseness of the process. By examining these grades, manufacturers can predict the outcomes—whether they’ll have neat square corners, coarse edges, or a taper cut. High cutting-edge quality signifies a finer finish and more precise parts.

How Precise is a Waterjet Cutting Machine?

The precision of a waterjet cut refers to the discrepancy between the actual cut and its intended path. Lesser the deviation, more accurate the cut, and consequently, better the edge quality.

This deviation, termed ‘tolerance’, is ideally minimized for achieving superior cut-edge quality. While zero tolerance is virtually unattainable in any machining process, waterjet cutting pushes this limit, thereby being recognized for exceptional edge quality.

Decoding the Different Waterjet Edge Quality Grades

Waterjet edge quality is categorized into five distinct classes, graded from 1 to 5. Let’s dissect each grade with specific details about its use-cases and cutting speed:

Grade 1: Quick Separation Cut (Q1)

Quick separation cut (Q1) is chosen for rapid part production, resulting in a rougher edge quality with noticeable striations, despite having high cutting speeds.

• Speed: Very Fast
• Quality: Poor
• Striations: Highly Visible

Grade 2: Through Cut (Q2)

Through cut focuses on speed while minimizing striations. Though still relatively rough, Q2 offers a gentler finish compared to Q1.

• Speed: Fast
• Quality: Below average
• Striations: Visible

Grade 4: Fine Edge Finish (Q4)

A fine edge finish, synonymous with high-cut quality, offers barely noticeable striations, though at a slower cutting pace.

• Speed: Slow
• Quality: Good
• Striations: Barely Visible

Grade 5: Superior Edge Finish (Q5)

Superior edge finish offers the pinnacle of cut quality. Striations are virtually non-existent in this grade.

• Speed: Slowest
• Quality: Excellent
• Striations: Absent

The Versatility of Waterjet Edge Quality Mixing

Different waterjet edge qualities can be effectively combined by tweaking the machine’s cutting speed. This strategy is beneficial when cutting internal and external sections of a part simultaneously. Less visible internal areas can be cut with lower quality edges, while more prominent external areas can utilize Q4 or Q5 edges.

The Factors Shaping Waterjet Edge Quality

Several factors influence the edge quality of waterjet cutting, primarily factors that impact precision.

Here are some key elements to consider for achieving the best cut quality:

• Cutting Speed:

• This is a vital determinant in waterjet cutting quality. Slower speeds yield better edge quality, but extremely slow speeds can lead to increased kerf angle.
• Abrasive Mixing Tube Length: In most waterjet cutting, abrasive material is added into a mixing chamber. A longer mixing chamber ensures uniform abrasive mixture, while shorter tubes may compromise edge quality.
• Waterjet Stream Diameter: A smaller diameter stream leads to higher-quality cuts, although at a reduced speed. Thus, the diameter of the waterjet stream and the nozzle size significantly affect cutting edge quality.
• Nozzle Height: The height of the nozzle can make a big difference in edge quality. A higher nozzle can round off the top edge of the cut and increase the kerf angle. A lower height is usually preferred for superior quality cuts.

How Material Properties Impact Cut Quality

The nature of the workpiece material can greatly affect the cut quality. In this regard, a material’s machinability is key. 

Poorly machinable materials can result in striations or rough edges even when using Q5 cuts. These require extra precautions, depending on the material type.

Conversely, materials with excellent machinability can yield exceptional edge quality even at Q3 and Q4 speed settings.

The Influence of Material Thickness on Edge Quality

The thickness of the material plays a significant role in edge quality.

Thinner materials often exhibit superior edge quality, even at higher cutting speeds, due to a lower likelihood of layered striations.

Thicker materials have a higher potential for striations, so slowing the cutting speed yields the best edge quality results. The same applies to stacked workpieces; lower layers may display slightly diminished cut quality compared to the top layers.

The Role of Software in Achieving High-Quality Cuts

Top-tier CAM software can greatly contribute to achieving consistent high-quality results. It effectively processes changes in geometry along with alterations in feed rate and other parameters.

High-quality CAM software optimizes these transitions, providing superior results. Substandard software, on the other hand, can result in poor-quality transitions such as corners and lines to curves.

The Effect of Abrasive Usage on Cut Quality

Indeed, the use of an abrasive can influence waterjet cutting quality. Abrasive waterjet cutting yields better quality results when working with harder materials. On the other hand, pure waterjet cutting is more suitable for softer materials like rubber and paper due to a narrower kerf width.

Choosing the Ideal Waterjet Edge Quality for Your Project

While Q5 edge quality is the gold standard for any project, its slower speed can be a hurdle for manufacturers aiming for high-volume production.

Moreover, superior waterjet cutting grades imply higher production costs. As such, many manufacturers opt for Q5 as the most cost-effective yet acceptable quality grade.

Guidelines We Follow To Maximize Our Waterjet Cut Quality

Here are some strategies we put into practice to refine the quality of our waterjet cutting process:

1. Use The Right Software: Service providers who use high-quality nesting software can be the differentiator between smooth and rough edge quality. We only utilize the top-tier nesting software with our machines, saving you the hassle of seeking suitable CAM software.

2. Regular Calibration: Improper calibration can lead to undesirable defects in waterjet cut parts. Therefore, precise calibration is essential before operating the machine, which is why we regularly calibrate our machines.

3. Selecting the Appropriate Garnet: Uniform garnet of fine size yields the best quality results. However, it also escalates the cost of the abrasive process. Hence, strike a balance between garnet quality and the price of waterjet cutting.

4. We Regulate Water Pressure: Some operators mistakenly believe that higher water pressure is needed for cutting harder materials. However, every material has an optimal water pressure for best results. We stick to the manufacturer’s guidelines in this respect.

5. Maintaining Our Equipment: Waterjet machines are heavy-duty industrial tools that require regular maintenance. We adhere to the manufacturer’s maintenance schedule. Certain components like nozzles and seals need replacement after specific intervals.

6. We Conduct Regular Tests: Before starting your actual project, we cut a test piece from the same material. This preview will help us adjust machine settings as needed for the final output.

In conclusion, waterjet cutting is a favourite choice among professionals due to its high-quality results. By following the above mentioned guidelines, we can achieve even greater accuracy and edge quality.

Our waterjet cutters can deliver all five grades of cutting edge quality. Don’t hesitate to contact us and receive professional advice from our experts on your next project.