Tag: maintenance

Achieving top-notch cut quality with plasma cutting involves understanding the main factors that impact the results. In this blog guide, we’ll explore these crucial elements to help you get the best possible cut every time.

The 7 Key Factors: 

1. Amperage (Cutting Current)
2. Gases Used for Plasma Cutting 
3. Arc Voltage
4. Torch Height
5. Cutting Speed
6. Kerf Width

1. Amperage: The Power Player   

Amperage measures the flow of electrons in an electrical circuit. Higher current levels can reduce dross (the unwanted material that forms on the edge of a cut) for a given material thickness. For instance: 

I_c = 260 Amp; Thickness 1 inch, mild steel, cutting speed 66 inches/min

A lower current level usually results in better edge quality and squareness for a given thickness, but maximum dross formation.

I_c = 260 Amp; Thickness 1 inch, mild steel, cutting speed 66 inches/min

Bonus tip: Lower current consumables generally last longer, especially when cutting with oxygen.

To ensure optimal amperage performance, it’s also essential to maintain a clean and dry air supply system, with regular checks on air quality, gas quality, and CFM (cubic feet per minute) flow rate.

2. Choosing the Right Gases

The purity of gases used in plasma cutting is critical for maintaining cut quality and consumable life. Here’s a quick guide:

Oxygen (O2) and Nitrogen (N2): O2 at 99.5% purity, N2 at 99.99%.

Argon-Hydrogen (H35) and Nitrogen-Hydrogen (N5): H35 at 99.995% purity (65% Argon, 35% Hydrogen), N5 at 99.98% purity.

Air: Should be clean, dry, and oil-free.

Methane: 93% pure.

Typically used plasma gases include Compressed Air, Oxygen, Nitrogen, and Argon-Hydrogen. Shielding gases help in arc constriction and cooling, enhancing the cut quality by reducing oxidation at the cut edge. The choice of gases depends on the material you’re cutting and the desired cut quality. Always refer to the manufacturer’s instructions for the best results.

3. Arc Voltage: The Balancing Act 

Arc voltage is crucial for controlling the torch height and, consequently, the quality of your cut. Higher arc voltage means a taller torch height, which affects the bevel angle and overall cut quality.

Keep an eye on the cutting speed—it directly influences arc voltage. As speed increases, voltage drops, and vice versa. This relationship is vital for maintaining quality cuts, especially around corners and intricate contours.

Relation between the arc voltage and cutting speed.
(Note: Graph is dependent on system and metal thickness)

THC (torch height control) reacts like this: The torch will lower as speed decreases, or rise as speed increases. THC must be turned off or “AVC Disabled” when speed decreases.

4. Torch Height: The Perfect Distance 

Getting the torch height right is key, especially during piercing and cutting.

Piercing Height: Set at 1.5-2 times the ideal stand-off distance.

Cutting Height: Maintained during the cut for optimal results.

How does it work? The torch height control system (THC) adjusts the torch based on the surface, ensuring consistent cut quality. Remember, the THC is “blind” before cutting starts, so it must first touch the material to detect the initial position.

5. Cutting Speed: The Sweet Spot

Speed is everything when it comes to plasma cutting. The correct cutting speed minimizes dross and ensures a clean cut. Follow the cutting charts provided by your equipment manufacturer to find the optimal settings for amperage, arc voltage, and torch-to-work distance. Proper handling and storage of consumables is also crucial to prevent damage and contamination.

Example of plasma arc formation
From left to right: Low cutting speed, Correct cutting speed, Fast cutting speed

6. Kerf Width: Precision Matters

Kerf width, the void created by the cutting process, is crucial for the dimensional accuracy of your parts. A wider kerf is often the result of slower speeds or higher power settings. Typically, kerf width is about 1.5-2.0 times the nozzle’s orifice diameter. Regular torch maintenance and proper mounting on the gantry arm ensure accurate kerf width control.

7. Coolant Condition

Regularly replace the coolant (every 6 months or quarterly for heavy use) and completely flush the system to prevent performance issues and torch failure.

By considering these critical factors, you’ll be well on your way to achieving top-notch plasma cutting quality and optimizing your workflow. Remember, attention to detail is key to producing precise, high-quality cuts.

Text:               Thermacut®
Photo:            Archive of Thermacut, k.s.

Are you in the world of metal fabrication? Choosing the right power supply can make a significant impact on the quality of your work. The decision to purchase a plasma cutter is about more than the type of work you intend to perform. Several factors make plasma cutters a good choice for busy manufacturers, DIY, artists, and small workshop cutters who wish to upgrade fabrication processes by adding precision, speed, and capability.  

This guide provides insights into some crucial questions to consider before selecting a plasma cutting system tailored to your requirements. 

Table of Contents: 

1. What material can be cut with a plasma cutter? 
2. How much is a portable plasma cutter? 
3. Why is the duty cycle important?  
4. Are plasma cutters portable? 
5. What power is needed? 
6. What PPE to wear for plasma cutting? 

1. Ideal Materials for Plasma Cutting   

Steel and aluminum alloys are considered ideal for plasma cutting. Both contain highly conductive properties. Electricity and heat can flow through Brass and copper similarly, due to how heat dissipates over these materials, specialized techniques and consumables can be employed to cut similarly to titanium, and anything with thermal conductivity or resistances drastically different from steel and aluminum alloys. 

2. Cost Considerations: Plasma Cutter Pricing 

Portable plasma cutting machines priced under $500 are often designed to be smaller and more compact, making them convenient for lighter cutting tasks or simpler projects. However, machines that boast higher amperage levels, durable duty cycles, precise cutting technology, compatibility with CNC systems, and a reputable brand can command prices as high as $20,000. Typically, machines that offer this comprehensive set of features tend to average between $3,000 and $5,000 in cost. These mid-range machines strike a balance between performance, advanced capabilities, and affordability for various cutting needs. 

3. Understanding the Significance of Duty Cycle 

Duty cycle indicates the proportion of time a machine can run without overheating within a set duration. For instance, in a 10-minute cycle, a 60 percent duty cycle allows the machine to run smoothly for 6 minutes, which is 60% of the total time. Factors such as output power and material thickness impact this operational duration. Machines with a duty cycle below 100% need intermittent breaks within 10 minutes, essential for plasma cutters and other electrical tools to prevent overheating. 

4. Assessing the Portability of Plasma Cutters 

Plasma cutters vary in portability depending on size, weight, and design features. Smaller, more compact models are easier to maneuver. Larger and heavier plasma cutters, while powerful, are typically less convenient to move around and are better suited for stationary or more industrial applications where mobility isn’t a primary concern. Some plasma cutters include features like handles or wheels to enhance portability, making them easier to transport from one location to another. Overall, the portability of a plasma cutter depends on its size, weight, and specific design features.  

5. Required Power Specifications for Plasma Cutters 

Plasma cutters have specific power requirements including voltage, amperage, and phase ratings for your outlets. Smaller models commonly use 120 or 240 volts on a single-phase power system, while larger models operate on 3 phase power and may require a breaker rated for 40 amps. Some plasma cutting systems can automatically adapt to different voltages. Reviewing the plasma cutter specifications and documentation to find voltage and amperage. Regular circuit breakers are typically rated for 15 or 20 amps, insufficient for a plasma cutter. Upgrading the circuit or installing a heavy-duty breaker connected to the outlet with a higher amp rating can address this. The latter allows a dedicated circuit for the cutter while enabling other workshop outlets for general use, though it involves additional expense for the new outlet. 

6. Essential Personal Protective Equipment (PPE) for Plasma Cutting 

Eye and face protection

Eye and face protection is vital during plasma cutting to shield your eyes from intense light (UV rays), debris, and sparks. While safety glasses are the minimum recommendation, using a welding helmet or face shield offers superior protection. Choosing the right shade level for the welding helmet according to the plasma cutting current ensures optimal eye protection. 

Clothing made from flame-resistant materials is essential for plasma cutting safety. Wearing long-sleeved, fire-resistant jackets, and pants provides effective protection against sparks and burns. 

Plasma Cutting Current	Welding Hood Shade Level
40 to 60	6
60 to 80	8
80 to 300	8-10

Hand protection

Hand protection is critical; opt for heavy-duty, heat-resistant gloves to shield your hands from burns and sparks. Gloves that balance heat resistance with dexterity aid in maneuverability and protection. 

Respiratory protection

is necessary, especially in confined or indoor spaces during plasma cutting. Use a respirator and ensure proper ventilation to prevent inhaling hazardous fumes or gases, safeguarding your respiratory system from potential harm. 

Ear protection

Ear protection is paramount in environments with excessive noise levels, such as when using a downdraft table during plasma cutting. Utilize properly fitted earplugs, earmuffs, or a combination of both to protect your hearing, especially when sound levels exceed 100 decibels. 

Source	Level
Gas Lawn Mower	80-85dB
Plasma Cutting	100dB+
Rock Concert	110dB+

Text:               Thermacut®
Photo:            Archive of Thermacut, k.s.

Plasma cutting machines are becoming increasingly used in a wide array of applications. Any Investment in new cutting equipment is a significant decision where major breakdowns or minor performance decreases can affect overall productivity.

Budgeting, assessment of market offerings, and consideration of return on investment are all important factors to ultimately make a well informed decision in purchasing any product and particularly when choosing the right plasma cutting machine.

Proper maintenance and regularly checking vital components ensure equipment maintains excellent condition. Regular service, upkeep, and adhering to manufacturer recommendations all support the optimal performance levels and promote high quality results.

In this brief guide we’ll highlight some maintenance ideas and intervals that can help to ensure components in your plasma cutter keep operating smoothly.

Why is maintenance important? 

Maintenance for plasma cutting machines is crucial, falling into three key categories: safety, ROI, and performance. Safety is paramount, ensuring industrial machinery operates without risks. Regular maintenance extends machine lifespan, improving ROI, and maintains top-notch cutting quality and efficiency.

Before each use

1. Inspect the torch body and handle. If the torch body is cracked, it will collect more debris affecting safety. Any damaged components should be repaired or replaced to prevent gas leaks and ensure safe operation of the plasma cutter.

2. Check the power cable and leads for any cuts, fraying, or exposed wires. Repair or replace if damage is found. Any twists or high-strain points in the wire should be further inspected for damage that could affect performance of the plasma cutting system.

3. Ensure the correct installation of consumables. Check the orifice is round and free of any debris lodged between the shield and nozzle. Apply a thin coat of dielectric to the torch O-ring if it is dry. If the O-ring is missing or damaged, replace it with a new lubricated o-ring.

4. Connect the system to the input power supply, release pressure on the gas regulator, connect the air line, switch the system to the “ON” state. After the automatic diagnostic check, inspect and if needed, adjust the air pressure to the desired value. Once all checks and necessary adjustments are made, proceed with usage.

Daily checklist

1. Inspect the torch body for cracks or exposed wires. Check handheld torch safety trigger for debris and test proper operation.

2. Remove power and Inspect cap sensor safety switch behind consumables. Ensure free of debris.

3. Check all cables for strain relief and power cords for wear, and exposed wires. Correct issues and replace cables or wires if needed.

4. Check connector hoses, and connections. Ensure fittings are secure and free of damage. Replace if necessary.

5. Check the work lead clamp and ensure tight fit to avoid arcing and contamination.

6. Check torch consumables for wear.

7. If your machine has any sensors, ensure proper operation.

Weekly Maintenance

1. Ensure proper operation of safety switch to prevent accidental firing during use of handheld or mechanized torches.

2. Clean machine with degreaser and a rag to remove any excess metal, dirt, and grease.

Monthly Maintenance

1. Maintain primary air filter and any accessory air filters.

2. Inspect fiilter for dirt and o-ring for wear, cracks and pinches.

3. Verify clean, dry, air free of oil or contaminates from air compressor to plasma cutter, purge excess moisture buildup.

Every 3 Months

1. Check the cutting torch exposed wire or cracks in the torch body.

2. Check the gas hose, filter elements and connections for leaks.

3. Check with your manufacturer to determine if any new maintenance is recommended, cleaning with compressed air can keep your machine at peak performance.

Annual Maintenance

1. Have a professional safety inspection performed by a trained technician if removing the cover.

2. Examine maintenance logs and assess future maintenance requirements.

If any damage is found during an inspection, always identify and assess any damage to the input power lead/plug, torch, torch lead, airline hose, connectors, or filter components. When necessary, repair or replace the damaged components accordingly. Do not operate the system unless it fully complies with safety standards. Always take necessary precautions to avoid exposure to dust and contaminants. Prioritize your safety, the safety of your colleagues, and the environment. Wear the appropriate Personal Protective Equipment (PPE) as required by your organization and local laws.

Text:               Thermacut®
Photo:            Archive of Thermacut, k.s.