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Satisfy the team – Rafal

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Becoming a member of Alpha Producing in excess of 9 a long time in the past, Rafal Laczkowski has develop into essential in making certain our products get to our buyers in pristine situation as promptly as possible.

Rafal joined the business in the dispatch division. After just one yr of doing the job within just the staff, Rafal’s challenging operate and motivation have been recognised – earning him a promotion to supervisor level.

Despite his enjoy for his staff and travel to assure his position was accomplished to a substantial standard, Rafal experienced often dreamed of a unique profession route.

Following 8 many years inside Alpha Producing, viewing the opportunities as a result of coaching and expansion offered, Rafal made a decision it was time to chat to Paul Clews, Taking care of Director of Alpha Production, about his childhood aspiration.

Rafal stated, “To be a driver, it was my aspiration. A right dream. Soon after 8 several years doing the job for Alpha Manufacturing, I approached Paul Clews and questioned him if there had been any opportunities to develop into a HGV driver.”

Alpha Manufacturing is dedicated to supporting apprentices and staff to achieve their most effective. This situation was no different. The Alpha management group agreed to cover all prices of Raf’s teaching and ensure him a position as a shipping driver upon completion.

Paul Clews, Handling Director of Alpha Production, reported, “I’m so proud that we have been able to assist Raf get to where by he needed to be. It is significant to us as a small business to know our staff are joyful and fulfilled.”

“A important target of The HEX Group is to ensure our crew has the teaching prospects to attain their objectives.”

Reflecting on the transition to his new aspiration function, Rafal claimed, “I’ve been driving for just more than a yr now. This work is best – from commence to finish.”

“My standard working day starts with vehicle inspections, guaranteeing the car or truck is harmless on the street. Then, it’s time to supervise the merchandise hundreds making sure that every thing is secured effectively to avoid hurt.”

“I can be executing a few of deliveries a day or undertaking just one for a longer time supply to spots these as Southampton. When I’m driving, you can uncover me listening to the likes of Michael Jackson, the Pet Store Boys, and other pop classics to move the time.”

Rafal’s determination to making certain that Alpha Manufacturing’s products get to our consumers is second to none. We appear ahead to sharing much more about his function below soon.

Plasma Arc Welding (PAW) Explained

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Plasma welding is an arc welding process that uses a plasma torch to join metals. The principle of this method is derived from GTAW aka TIG welding, where an electric arc is struck between the electrode and the workpiece.

Let’s dig deeper and explore what plasma welding is all about.

What Is Plasma Welding?

Plasma arc welding (PAW) is a fusion welding process that uses a non-consumable electrode and an electric plasma arc to weld metals. Similarly to TIG, the electrode is generally made out of thoriated tungsten. Its unique torch design produces a more focused beam than TIG welding, making it a great choice for welding both thin metals and creating deep narrow welds.

Plasma welding is often used to weld stainless steel, aluminum, and other difficult metals compared to traditional methods. Similarly to oxy-fuel welding, this process can also cut metal (plasma cutting), making it a versatile tool for fabricators and manufacturers.

Plasma Arc Welding Process




Plasma Arc Welding

The plasma arc welding process revolves around the principle of striking an arc between a non-consumable tungsten electrode and the workpiece. The plasma nozzle has a unique design feature, where the electrode is located within the body of the torch. This allows the arc plasma to exit the torch separated from the shielding gas envelope.

Additionally, the narrow opening of the nozzle increases the plasma gas flow rate, allowing for deeper penetration. While filler metal is typically supplied at the weld pool’s leading edge, it is not the case when creating root pass welds.

The complexity of the plasma welding torch sets it apart from gas tungsten arc welding. Plasma welding torches operate at very high temperatures, which can melt away their nozzle, making it a requirement to always be water-cooled. While these torches can be manually operated, nowadays, most modern plasma welding guns are designed for automatic welding.

The most common defects associated with plasma welding are tungsten inclusions and undercutting. Tungsten inclusions occur when the welding current exceeds the capabilities of the tungsten electrode and small droplets of tungsten get entrapped in the weld metal. Undercuts are generally associated with keyhole mode PAW welding and can be avoided by using activated fluxes.

Plasma Arc Welding Operating Modes

Three operating modes are used in plasma welding, wherein it can be operated at varying currents:

Microplasma (0.1 – 15A)

This operating mode can run arcs at low currents and remain stable up to 20mm arc length.

Microplasma welding is used to join thin sheets up to 0.1 mm in thickness, which is optimal for creating wire meshes with minimal distortion.

Medium current (15 – 200A)

The characteristics of the plasma arc are quite similar to TIG welding, but the arc is stiffer since the narrow opening of the torch restricts the plasma. We can increase weld pool penetration by speeding up the plasma flow rate, but this increases the risk of shielding gas contamination.

Medium current or melt-in mode offers better penetration than TIG and improved protection. The only drawback is that the torch requires maintenance and is bulkier compared to a TIG torch.

Keyhole mode (over 100A)

A powerful plasma beam is used to engage in high-current aka keyhole mode by increasing the gas flow and welding current. This mode allows deep penetration, using a single pass (up to 10mm thick for some materials) to create a consistent weld pool from molten metal.

Similarly to electron beam welding, the keyhole mode is great for welding thicker materials at high welding speeds. To guarantee satisfactory welds, filler material is generally added. Its welding applications include mechanised welding, positional welding, and pipe welding.

Comparison of Plasma and TIG Welding

Normally, a tungsten electrode is used in TIG welding to strike an arc between the torch and the workpiece. The plasma process works similarly but uses a different setup in its welding torch. The constricted nozzle design allows electrons to move at high velocities. This ionises the gas, creating a plasma jet with a high heat concentration, offering deeper penetration.

As plasma welding offers greater precision than TIG welding, it has a smaller heat-affected zone which is perfect for creating narrower welds. Ideally, plasma welding is a better choice than TIG welding, as it is an evolution of the latter. The technology behind its equipment allows it to run with lower current demand, better arc stability which leads to better stand-off distance, and better tolerances if the arc length is changed.

TIG welding however is a simpler method due to the complex parameters available for plasma gas welding. An operator would need extra training in order to transition from the already advanced TIG welding to PAW. And last, TIG welding equipment is cheaper and requires less maintenance than plasma arc welding’s sensitive and complex torch.

Materials

Similarly to TIG welding, plasma welding is suitable for the majority of well-known metals, although it might not be the most cost-effective solution for some of them:

  • Alloy Steel

  • Aluminium

  • Bronze

  • Carbon Steel

  • Copper

  • Iron

  • Inconel

  • Lead

  • Magnesium

  • Monel

  • Nickel

  • Stainless Steel

  • Titanium

  • Tool Steel

  • Tungsten

Equipment

The key components of plasma welding equipment are:

Plasma torch

Plasma arc welding (PAW) torch operating principle
Plasma torch – plasma gas is separated from the shielding gas envelope.

 

The unique design of the water-cooled plasma torch is the main distinguishing factor from other welding processes. Its operating principles have already been explained in previous sections.

Depending on the weld material and desired weld characteristics, different types of nozzle tips can be selected.

Control console

While conventional welding techniques directly connect a torch to a power source, plasma arc welding uses a control console between the two.

Some of the console features are the torch protection circuit, high-frequency arc starting unit, power supply for the pilot arc, water, and gas valves, individual meters for plasma, and shielding gas flows.

Power supply

Plasma arc welding uses DC power (rectifiers or generators) of at least 70 volts for open circuit voltage with drooping characteristics to have greater control in generating weld beads.

Gases used

  • Plasma gas – exits the constricting nozzle separately from the shielding gas envelope and becomes ionised

  • Shielding gases (argon, helium, hydrogen) – inert gas protects the weld from the atmosphere

  • Back-purge and trailing gas – certain materials require special conditions

Wire feeder

Plasma welding may use wire feeders with a constant velocity that can be modified to run from 254 mm per minute to 3180 mm per minute.

Applications

Steel tubes

PAW is a great welding method in manufacturing steel tubes as it can be performed at high-speed welding with great metal penetration. Some industries prefer the plasma welding process to conventional TIG since its system is faster and uses less filler material.

Electronics

One of the welding parameters of the plasma welding process is it can run at low current modes. This mode allows small metal component welding, which deals with delicate materials sensitive to environmental factors.

Medical industry

Medical devices require precise components in order to run effectively. PAW is perfect for welding these components as it can reliably create a consistent weld bead.

Advantages of Plasma Welding

  1. Can be operated in every welding position.

  2. Fast travel speeds from concentrated heat input.

  3. Keyhole welding allows for complete penetration.

  4. Low current mode is suitable for thin and sensitive components.

Disadvantages of Plasma Welding

  1. Expensive equipment and components.

  2. Requires training and skill to create good welds.

  3. Produces 100dB noise.

  4. Creates ultraviolet and infrared radiation.

  5. Water cooling is necessary because of high working temperatures.

  6. Delicate equipment needs a higher amount of maintenance.

Pricing for Inventor Documents Now Obtainable

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In addition to the aid for SolidWorks documents we additional before this calendar year, we’re now ready to quote file sorts native to Autodesk Inventor as properly.

The listing of file sorts our platform can now quotation is as follows:

  • .ipt – Inventor section file
  • .sldprt – SolidWorks aspect file
  • .stp – the universal 3D CAD file 
  • .dxf –  2D drawing file (can quotation flat laser reducing work opportunities)
no price difference
.stp or .ipt, no change in pricing

So as you can see from the screenshot above, there is no require to commit time changing the files to .stp when using Inventor from now on. 

Sheet Metal Hemming | Hem Types & Processes Explained

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Hemming is a common metalworking process mainly carried out to reinforce an edge, hide burrs or just improve the overall appearance of sheet metal parts. When hemming is carried out in a way that a joint between two sheet metal parts is created, it is called seaming but more on that later.

So, without further ado, let’s dive into the subject.

What Is Sheet Metal Hemming?

Hemming in sheet metal operations refers to the bending of a sheet metal edge onto itself. It is very similar to edge stitching in clothes. Similar to how an edge stitch strengthens the edge and makes it more durable, a hem imparts strength to the metal edge and improves its appearance. The edge of one part may also be folded onto another part to create a joint.

Hemming is usually done in two stages. The first stage creates an acute bend using acute tooling (V die) followed by a flattening of the return flange using a flattening die.

A complete list of hemming benefits on a sheet metal product is as follows:

  • Hems strengthen the sheet metal edge

  • They improve the surface appearance and surface quality

  • They hide defects such as rough edges and burrs

  • They can connect parts

  • They make the edges safer to handle

Hem Types

The different sheet metal hems based on the hem shape are as follows:

  • Flat or closed hem

  • Open hem

  • Teardrop hem

  • Rope hem

  • Rolled hem

Flat or closed hem

In a flat or closed hem, the part of the edge that bends sits completely flush over the rest of the metal sheet. The angle between the returning flange and the sheet metal is 180 degrees. The inside radius is zero and thus, there is no gap between the returning flange and the metal sheet.

Closed hems require a lot more power and tonnage from the presses than open or teardrop hems and it is also not advised for metal sheets that are over 2-3mm in thickness since the sheets are likely to fracture. 

Open hem

Sheet metal hemming types - open hem

In an open hem, the returning flange is folded over the sheet metal but there remains an air pocket between the two. The bend angle in this hem type is also 180 degrees.

Teardrop hem

Sheet metal hemming types - teardrop hem

In a teardrop hem, the returning flange is bent beyond 180 degrees. The resulting shape resembles a teardrop.

It is perfect for materials that do not have the required ductility to provide closed hems. Teardrop hems are used for fragile materials such as aluminium.

Rope hem

Sheet metal hemming types - rope hem

A rope hem has a returning flange at a bent of more than 180 degrees. Once the hem achieves the shape of an open hem, the returning flange is pressed onto the part surface through a flattening die.

The edge is bent in shape similar to an open hem and then the second piece to be connected is inserted into the gap between the metal sheet and the returning flange. Further pressing takes place making the second parts sit flush between the metal sheet and the returning flange and create a joint.

Rolled hem

Sheet metal hemming types - roller hem or curl

In a rolled hem, the bent portion of the sheet metal is tucked back into itself.  This creates smooth round edges all around for holding the part from the hemmed edges. This process is also commonly referred to as curling.

Hemming Process

The hemming process can be carried out in one of the following two ways:

  • Die hemming process

  • Roller hemming process

Die Hemming Process



Die hemming process


Die hemming process

Die hemming is the conventional hemming operation that uses a die and press to carry out hemming. In this process, the bending occurs along the full length at predefined angles in multiple steps. These steps are known as pre-hemming and final hemming.

For instance, when forming a closed hem, the edge will be bent to 45 degrees in the first step by passing it through a press brake. The next bent occurs by means of the same press brake but a different part of the tool that completes the closed hem.

The die hemming process is not very flexible and is generally restricted to the production of flat, uncomplicated panels. The investment in the equipment is high but the cycle times can be brought down to be quite low.

Roller Hemming Process



Manual Roller Hemming


Manual Roller Hemming

The Roller hemming process was invented to increase the flexibility of the hemming operation. It generally uses robots to control rollers that bend the edges but there are simpler manual roller hemming machines available that can handle only simpler tasks with less accuracy. The rollers travel along the edges and bend the part edge to the desired angle in multiple steps.

The orientation of the sheet may be changed multiple times during the hemming process to reduce the travel of the roller and increase the cycle time. Apart from the robot itself, this method is considered economical both for low and high-volume tasks. Robot roller hemming allows for jumping back on forth between producing different parts through quick program changes.



Robotic Roller Hemming


Robotic Roller Hemming

Hemming and Seaming Difference

A seam is used to connect two metal parts by interlocking the edges of the folded sheet metal parts. The resulting shape may even form a seal that isolates one side of the sheets from the other.

As a result, seaming finds use in sealing canned goods in the food industry. Hemming and seaming come across as very similar processes but there are some key differences.

These differences are as follows:

  1. A hem’s return flange sits flush on the metal sheet in some cases but in seaming, the return flange never sits flush. There is always some gap.

  2. A hem’s primary purpose is to reinforce the edges and improve the appearance. In seaming, the primary purpose is to connect two parts.

  3. A seam may be used to seal one end of the two sheet metals when joined as seen in canned goods. A hem is never used for this purpose.

  4. They are both used in different applications. Hemming finds use in automotive and aerospace industries but is also suitable for a lot of general applications. Seaming typically finds use in the food industry, metal roofing, and the automotive industry to some extent.

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