But does True Hole Technology truly help deliver a superior cutting result and is it worth investing in?

Absolutely!

Do you need to cut a hole with ratio 1:1 or bigger in mild steel? In other words, do you want to cut a hole with a diameter as thick as the plate? All you need is a robust plasma cutting table and CAD/CAM software that is able to output holes as True Hole holes. With those 2 ingredients, you’re set for superior hole quality in the long run in a mild steel application. This will allow you to produce your parts internally instead of having to outsource them to an external profiling centre

But understanding how True Hole works and how to make it best work for you is not always straightforward.

We’ve tried to make this article the most useful stop on your journey to a solution by answering the 10 most frequently asked questions on this topic!

Why does True Hole technology exist?

Metal components for various applications frequently require holes of various sizes (e.g. to fit bolts). Historically, plasma cut components were known to deliver poorer quality holes than often required.

For example, plasma cut holes would be tapered and could have a “ding”. You could observe this when during the lead-in/out a small amount of material is left, which is protruding into the area of the hole.  This could stop a bolt or pin from being inserted through the hole.

‘Ding’ as an effect of straight lead-ins

Due to this imperfection secondary operations were needed to complete the job and make sure every hole was up to the right spec. This is not only very time consuming but could slow down the entire production process when it becomes the bottleneck.

Can these costly secondary operations be avoided?

Yes. But first, you need to appreciate the complex nature of cutting a bolt-ready hole with plasma. It requires:

• The right dimensions between thickness and hole diameter (min 1:1)
• A robust CNC plasma cutting machine, which is able to produce repeatable results with high accuracy, staying on the cut path with high accuracy
• A specific plasma torch and consumables design 
• The part design (lead-ins, lead-outs, etc.)

To manage all these complex actions simultaneously and hence to avoid costly secondary operations, Hypertherm introduced its True Hole technology in 2008.

This innovative technology enables high-performance plasma cutting machines to produce plasma cut “bolt quality” holes, 100% of the time, and without additional operator intervention.

With plasma technology now being able to deliver significantly better hole quality compared to older systems, it has become a much cheaper and reliable solution for manufacturers that need top-notch hole quality.

Although at this time, True Hole technology is only applicable to mild steel components, the technology has seen continuous significant upgrades over the last decades. Working together with advanced CAD/CAM software such as Esprit’s Procut, Hypertherm’s True Hole technology was significantly upgraded with the introduction of the latest XPR300 plasma cutting systems in 2017.

‘no Ding’ due to a smooth transition with semi-circle lead-in and optimized lead-in speed

What are the benefits of True Hole technology?

The main benefit of true Hole technology is that it delivers “bolt-ready” quality holes automatically and without operator intervention.

Holes are much more cylindrical (less tapered) and have a much less pronounced “ding” which does not protrude into the hole.

Both of these improvements allow bolts to be readily inserted into plasma cut holes produced using True Hole technology. This further enhances the quality of plasma cut components resulting in the plasma process being suitable for many jobs previously cut with laser.

Secondly, getting good holes requires fewer skills. Whereas hole cutting on most CNC machines used to require a lot of technique & experience to manage the complex interaction between mechanical parts, height settings, cut speeds & gas flows, True Hole technology automates the parameter settings to deliver the optimal results.

Businesses with this technology are a lot less dependent on an operator to deliver high-quality parts.

Thirdly, depending upon the hole size (relative to thickness) required, the technology may enable plasma cutting as a solution where previously laser was the only option.

For those manufacturers that are currently outsourcing their cutting applications to an external laser cutting service, True Hole has opened up the possibility to bring the production of parts with holes back in-house, allowing to have full control over the supply chain without having to purchase an expensive laser cutting machine.

‘Bolt Hole Quality’ with True Hole Technology

What are the limitations of True Hole?

       Material:

Currently, True Hole technology is only available for mild steel. In case your application requires cutting a different material, you might still need secondary operations in case of imperfections.

Your Application:

Although the technology can guarantee adequate bolt hole quality, it might sometimes not be enough if you require even higher accuracy (e.g. a PCD or 4 bolt pitch for a motor or pump to go on). For those applications, it might be more appropriate to outsource your parts to a laser cutting service or cut them on your laser cutting machine.

Thickness Ratio:

Then, True Hole technology is optimized from a 1:1 to a 2:1 hole diameter to thickness ratio (2 times hole diameter vs plate thickness).

Yet, some manufacturers will have an extended version of True Hole. Some businesses require bolt quality holes beyond these ratios. For example, if you want to put an 80mm rod through a 20mm plate, the standard True Hole will not work for you.

However, you can only obtain extended True Hole variations by using an adequate nesting software package. For example, Procut has an extension, called Smart Hole, which extends a True Hole like cut quality up to 5:1 ratio. 

Your CAD/CAM Software:

Even if you have a Hypertherm power source that is True hole enabled (e.g. HPR260XD or XPR300), your machine may not have TrueHole holes at all.

After all, True Hole needs to be outputted by the post-processor of your CAD/CAM software. For example, ProNest and Procut do output TrueHole, whilst SigmaNest may not output True Hole holes. 

Many underestimate the importance of software and decide not to make this final investment.

But perhaps this analogy can clarify the importance of going with the right CAD/CAM software: it’s like giving an F1-car to a person without a driving license.

Although there is huge potential, without a proper pilot to control all this power you still won’t win the race.

Mechanisation:

Finally, True Hole is also not available for the lower-cost air plasma systems. As the technology requires auto-gas, it is exclusively available for use in conjunction with Hypertherm’s HPR-XD and XPR plasma cutting systems.

That means that you will need to trade up to a higher-end system and consequently a more expensive overall CNC machine.

However, most manufacturers that need to add “bold quality” holes in their mild steel applications agree that the extra investment is well worth the superior quality and efficiency.

If the highest accuracy is required a fibre laser is your best option

What are the minimum requirements for True Hole?

In order to utilize True Hole, your CNC plasma machine will need to meet the following requirements:

• True Hole is only available in conjunction with Hypertherm X-Definition™ XPR plasma cutting systems or HyPerformance Plasma HPRXD plasma cutting systems with an auto-gas console
• A CNC plasma machine with a True Hole-enabled CNC control.
• A Torch Height Control lifter system that is capable of locking out arc voltage and maintaining correct pierce and cut heights.
• A True Hole-enabled CAD/CAM nesting software package, e.g. Procut or ProNest.
• A cutting table with high-quality motion control.

‘Bolt Hole’ quality, right off the machine

How does True Hole technology work?

This paragraph will go in more depth on how the True Hole technology actually works.

In case you are not a technical operator and you immediately want to know more about the concrete impact on the cutting results, you might want to skip this part and go straight to the next section that explains the quality improvements you can expect.

True Hole technology is a specific combination of parameters that are optimized for mild steel hole quality, by specific amperage, material thickness, and hole size.

One of the key advantages of True Hole, in addition to improved hole quality, is the automation of certain parameter settings: process gas selection, gas flow rates, pierce technique, lead in/out techniques, cutting speeds and cut timing are all automatically applied by a True Hole enabled nesting software package and CNC.

The process of how this works is as follows:

How much will my quality level improve with True Hole technology?

True Hole technology produces significantly better hole quality than a plasma system without TrueHole. Hole taper will be virtually eliminated and ding will be reduced and biased to the outside of the hole, making the hole bold-ready.

However, that doesn’t mean the level of quality improvement cannot vary.

In fact, being bolt-ready doesn’t mean the hole will be perfectly round. The exact quality of each bold-ready hole can vary depending on the quality of the machine and the software used.

The motion of the table will directly influence the quality of the hole. The more precise the motion, the higher the quality. Using True Hole technology will deliver some improvement in hole quality on most cutting tables; however, tables with superior, precise motion control will provide the best improvements in hole quality.

For example, high-performance plasma cutting machines such as the Esprit Lightning HD and Viper have powerful AC brushless drives with high-quality planetary gearboxes which produce smooth, high-performance motion. These market-leading machine specifications combined with Hypertherm’s True Hole technology deliver the highest quality holes in plasma cut parts.

As we mentioned before, the true power of True Hole is also only unleashed when using the right software. If you read the detailed paragraph above on how True Hole technology actually works, you understand the critical role software plays both as architect before the cutting process starts, as well as skilled pilot managing the different parameters settings during the operation.

Taking all of this into account, it is strongly recommended checking the real-life quality of the holes before purchasing a new True Hole-enabled CNC plasma system and/or software package.

Cut samples should be obtained from the OEM table manufacturer to see the type of quality that is possible on their machines.

Request cutting samples from your OEM manufacturer

How does the hole quality compare to other cutting technologies?

When it comes to delivering superior hole quality, laser technology is often considered as the golden standard. In general, modern fibre laser cutting machines are indeed able to produce high-quality holes in components at a fast pace, and this as a result of their high dynamic machine performance and narrow kerf width.

The downside of laser technology, however, is that edge quality becomes a lot less smooth above 12-15mm and cut speeds decrease significantly vs plasma. On top of that, the investment for a laser cutting machine is a multiple of that of other technologies. As a result, many fabricators and manufacturers decide to outsource their cutting needs to an external laser cutting service.

Whilst benefiting from not having to do a major investment this comes at the cost of overall production flexibility. When you have a last-minute request from a customer, your laser cutting service may not always be able to deliver within the time you need the parts.

Oxy-fuel flame technology, on the other hand, is cheaper and has no problem piercing even thicker plates. However, the flame-cutting process is not really suited for cutting smaller holes in parts. The inferior hole quality does often require secondary processes (e.g. drilling or punching).

The latest developments in plasma cutting technology have delivered much higher hole quality than previously available, making plasma a suitable and very cost-effective solution when compared to other alternatives.

The additional thickness capability with plasma and the significantly lower capital costs give it a real advantage in many applications. Only when your application needs the highest accuracy a laser cutter is still recommended.

TIP: When comparing holes from different systems and technologies, firstly check the functionality of the hole. To easily test this, use a gauge pin or a bolt and try to push it through the hole. In the absence of taper, the pin or bolt will slide right through. In case of resistance or scrapping, you are dealing with an inferior quality hole.

Holes with XPR Plasma compared to Laser

When is installing or upgrading to True Hole technology a good idea?

In many applications, True Hole can eliminate the need for secondary drilling or punching operations and widen the application of the machine.

Customers with an application that requires quality holes who are in the marketplace for a new high-performance cutting solution should ensure that any plasma cutting machine they consider is True Hole capable.

To note, many of the attributes necessary for True Hole are perfect indicators of a high-quality plasma cutting machine solution: precision machine motion, best in class auto-gas plasma cutting technology, precision arc voltage height control and advanced CAD/CAM software.

But also existing users of a Hypertherm HPR plasma cutting systems (sold until 2011) requiring improved hole cutting capability should consider upgrading machines with True Hole technology, provided the existing machine is sufficiently engineered to exploit the process.

So, how can you get True Hole if you have an HPR plasma cutting system? 

First of all, you need to install Hypertherm’s XD upgrade package to upgrade your HPR plasma cutting system to HPRXD:

• New control board with firmware for the power supply
• New XD machine torch assembly which includes a quick disconnect torch and receptacle, torch sleeve
• New torch leads
• IHS ohmic contact wire, necessary for ohmic sensing
• HPRXD Auto Gas Selection Console

A second vital element to make sure you have a True Hole enable Controller. Therefore, if you have an older controller like an Edge1 or Edge2, you’ll have to upgrade it to an Edge Connect CNC system. 

A third key element is to have software that allows to output CNC files with TrueHole. You could work with Hypertherm’s own CAD/CAM part nesting software ProNest or advanced CAD/CAM packages like Procut.

In case you want more information on how much such an upgrade cost or if you want assistance with the installation, we recommend you to contact your table manufacturer.

How do I make the most out of True Hole Technology?

As we mentioned already a couple of times in this article, True Hole can be a very powerful tool & partner to deliver top-notch hole quality, yet the level of quality can differ depending on certain factors.

To make sure your CNC machine is set up to get the most out of this technology we have summarized 5 tips: 

Who can you contact if you need expert help?

If you are looking for a solution that delivers high-quality holes, but you are unsure which CNC machine & plasma system is right for your application, we are happy to help.

Our team of experts can not only help you to identify a tailored solution, but you are also warmly invited to visit our facilities where we can show you the cutting process and resulting hole quality during a live demonstration.

So contact us today for more information or to book a live demo. 

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Hypertherm, HyDefinition, HyPerformance, HPR, True Hole, True Bevel, XPR, X-Definition, ProNest and EDGE are trademarks of Hypertherm, Inc. and may be registered in the United States and/or other countries.