No more warranty claims for electric motors manufacturer

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When loose screws are causing downtime in your production and issues in your own maintenance processes, it’s certainly neither wanted nor pleasant. But when they cause warranty claims for the goods you’ve manufactured – then it’s downright embarrassing!

Costs of covering those warranty claims are certainly not negligible, but the damage caused to the brand value and customer trust is often immeasurable.

No more warranty claims_electric motor

And for the electric motors manufacturer in Asia it was a nightmare come true. Loosening of fasteners (although spring washers were used to lock them in place) on housing end bells was continuously leading to damage of the motors, after they have already been put in service, mainly caused by the vibration of the cooling fan.

Searching for a solution, it was quickly realised that a threadlocking method will have to be used which addresses the question of the gap between the fastener threads, if the same problem was to be avoided in the future. As it was a very standard threadlocking application, Loctite 243 worked perfectly on it, and just a few drops on every fastener prevented further warranty claims and helped restore the brand reputation.

In case you’d like to learn more about threadlocking on electric motors specifically, keep an eye out for a webinar on this topic, or simply contact us directly and we’ll be happy to talk about your specific requirements.

How to ensure Threaded Fastener reliability in electric motor

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Electric motors are the primary driving equipment in any plant and extremely critical to ensure uninterrupted productivity. However, the high vibration, thermal cycling and expected long service life can be challenging for these critical components.

There are a few very common challenges related to, for example, threaded fasteners on an electric motor.

Threaded fasteners in electric motor

The root causes of these failures are in their essence quite simple: vibration, torque and thermal fluctuations and corrosion. And all these failures can really be traced back to one thing – the gap remaining between the threads of the bolt and nut. Usually you don’t even think about how much metal to metal contact is there really between a nut and a bolt. And the fact that it’s only 15%, will shock most people. The remaining 85% is just gap. And this gap allows for a few unwanted things:

  • Vibration to cause side-to-side motion leading to self-loosening
  • Differential expansion and contraction of substrates due to service temperature changes
  • Corrosive environment to attack the metal fasteners

Conventional locking methods like lock washers, while providing some level of maintained torque for a period of time, do not close this gap and prove ineffective in locking and sealing threaded assemblies. A liquid threadlocker, on the other hand, addresses this issue exactly.

On a typical electric motor, you’ll likely need two products: Loctite 222, for small diameter and long engagement length bolts, like the motor through bolts, and Loctite 243 for all other bolts.

As a result, what these two products do for you is the following:

Threaded fasteners in electric motor_2

In case you’d like to learn more about threadlocking on electric motors specifically, keep an eye out for a webinar on this topic, or simply contact us directly and we’ll be happy to talk about your specific requirements.

Why is Loctite Threadlocker better than the ribbed flanged bolt

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Ribbed flanged bolts are among the more expensive of the bolts range. One of their main purposes is to eliminate the human error factor – someone potentially forgetting to include the toothed washer into the assembly – by already building it into the bolt’s head. The ribbed bottom of the bolt’s head bites into the surface and that way secures additional clamp load.

There are, of course, downsides to that. First of all, such a bolt needs a flange of sufficient size to work. Over time, it will ease into the surface, loosing clamp load, while potentially damaging the flange surface. The gap between the threads of the nut and bolt will remain unaddressed throughout and be the main enabler for micromovements and vibrational loosening, as well as corrosion due to moisture that can easily get to the threads.

With a liquid threadlocker, such as one of the Loctite products, the gap which is the root cause of all the bolt failures, is effectively eliminated and sealed.

Loctite Threadlockers pick’n’mix

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Using a liquid threadlocker will certainly simplify things in terms of types and sizes and quantity of different locking devices you need to keep on stock. And in roughly 80% of the cases a standard Loctite 243 will be all you need. However, there are certain specific applications, where you need to look into other available grades. And no worries, it’s still not going to be a hundred products to navigate through, comparing complex details. No, we are talking about a rather comprehensive range of four products that are likely to fit your requirements, whether your business is in heavy industrial equipment or delicate electronic components.

The main thing is to determine the needed strength level, the frequency of dismantling for maintenance and whether or not you might need to apply your threadlocker on already assembled pieces.

On the picture below, you can see the available products with the main technical characteristics to look into when selecting the one that’s right for you. The selection is rather straight forward and, as already mentioned, in big majority of the cases Loctite 243 does the trick, but it’s definitely recommended you look into our recommendation online or contact our technical customer service if you have any concerns.

Loctite threadlockers pick n mix

How a Loctite Threadlocker helps harness the sun’s energy more efficiently

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The efficiency of your manufacturing operation can depend on something as mundane as nuts & screws even when what you’re producing is – energy. Now, solar panels can appear as static an assembly as can possibly be, right? Well, only partly right.

It would be great if types of weather other than sunny could be removed from the equation, but that isn’t really possible, which means that the solar panels can be exposed to quite strong winds. Which causes just enough vibration for the panel mounting bolts to loosen after a few cycles.

Solar power plant article.jpg

Additional to that, they are constantly exposed to thermal cycling, as they get either directly exposed to the sun or shaded for a part of the day. Being made of metal, bolts will expand and then shrink again as these temperature changes occur, leading to additional loss of torque over time.

In a Japanese solar power plant, this happening repeatedly, led to loss of revenue for the time that certain panels were out of commission, as well as drove the maintenance costs up. As the maintenance engineers looked for a solution they came across a really handy product – Loctite 290. Loctite 290 is a high strength threadlocker, same as Loctite 270, but it has a characteristic which makes it unique – it has wicking properties. That means that the product will actively creep in between the two already joined surfaces, which in this case meant that it could be applied to the already assembled bolts and nuts.

For the power plant, this resulted in no more revenue loss, reduced maintenance costs and improved safety.

Loctite Threadlocker – removability & disassembly

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Advertised strength of the threaded assembly secured with a Loctite threadlocker can sometimes be the reason some engineers decide against them, fearing they may complicate disassembly which is necessary for repairs and regular maintenance. So, I feel I need to elaborate on that a bit.

Every assembly locked with a Loctite threadlocker can be dismantled – and I mean: every! It’s just a question of how and which method to use. When low and medium strength grades are used, the parts can be disassembled by using regular hand tools. In fact, the disassembly will be largely helped by the absence of any corrosion that usually occurs between the threads when no liquid threadlocker is used.

If a high strength grade is used, localised heat (up to 2500C) needs to be applied after which the same method of using regular hand tools works.

Looking at the video tutorial, it seems almost embarrassingly simple. So, in case you had any reservations related to disassembly, rest assured – there is no need for any.

A liquid Loctite threadlocker will improve reliability of your assembly for several reasons:

How to disassemble_reliability

On top of that, the clamp load retention is considerably better with a liquid threadlocker compared to mechanical devices.

How to disassemble_Clamp load retention

If you would like to test this yourself you can now request a sample of Loctite 243 from your local Loctite team (select your country at the top navigation on the website).

Why is Loctite Threadlocker better than castellated nut

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Among all of the mechanical locking devices, castellated nut with a split pin is likely the most complex one and it will typically be used on the more complex, high-tech, usually expensive assemblies. Implementing it correctly requires a certain amount of skill and precision (unlike with the double nuts or spring washers for example).

Apart from tightening it to the correct torque, precise alignment is needed for the split pin to go through. Regardless of the torque, the gap between the threads still remains, allowing for micro-movements under vibration once the assembly is in service. While castellated nuts are the most expensive among mechanical locking devices, and certainly not something you’ll want to have replaced too often, you will need to keep inventory of various sizes and types for regular maintenance and replacement when some of them fail or corrode. And they inevitably will because the gap between the threads allows for the moisture to get in.

With a liquid threadlocker, all of the mentioned issues can be avoided. You just need to choose the correct grade in terms of strength you want to achieve (low, medium or high), and a medium strength product normally covers a huge percentage of applications, and you can use it across wide range of your needs. A liquid product will also completely fill all gaps between the threads, sealing the assembly against moisture and preventing any type of movement under vibration.

That way your threaded assembly will stay locked for as long as you want.

5 reasons why Loctite 243 is a “must have” in your maintenance kit

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Loctite 243 is a medium strength threadlocker that secures all types of threaded fasteners like nuts, bolts and studs, at the same time sealing them against corrosion. While there are naturally exceptions in some cases, Loctite 243 will be suitable for the vast majority of standard threadlocking applications and you are unlikely to need another grade very often.

Reason 1:5reasons_reason1

Strengthens threaded assemblies against vibration by adding approx. 25% to the torque needed to loosen a normally tightened bolt assembly.

Reason 2:5reasons_reason2

One product for locking various sized fasteners, versus an inventory of different sized mechanical locking devices you would otherwise need to keep (saves both money and space).

Reason 3:5reasons_reason3

It’s suitable for active and inactive substrates. Do note though that activator Loctite SF 7649 is needed on inactive surfaces.

Reason 4:5reasons_reason4

It’s tolerant to minor oil contamination, curing on as-received fasteners without cleaning, or on parts that aren’t easily accessible for thorough cleaning during maintenance.

Reason 5:5reasons_reason5

Assembly locked by Loctite 243 can be easily disassembled, when needed, using ordinary hand tools.

In case you’ve never yet tried Loctite 243, you can now request a free sample and give it a go. (Please select your respective country at the top navigation before filling in the form.)

When to use Loctite Activator with your Loctite Threadlocker

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All metals are not exactly the same in their characteristics. That is a widely known fact in the engineering world. And hence, they don’t behave the same in how they interact with substances, in how they can be processed and handled etc. When it comes to bonding in general, and threadlocking specifically, there are two main types of metals to distinguish between: active and inactive metals.

Your typical active metals include iron, plain steel, copper, brass, bronze, nickel, manganese, Monel™ and Kovar™. With any one of these, in most of the typical cases, the bonding (threadlocking included) will work just fine without the use of any activator. You might still optionally use it, usually in the cases when you want to speed up the cure and achieve handling strength faster. But it will also work just fine without.

However, there’s also the other group, the inactive metals, such as (and this list is by no means exhaustive) any plated parts, anodised aluminium (i.e. Alodine® or Iridite™), titanium, stainless steel, galvanized steel, zinc, pure aluminium, cadmium, magnesium, natural or chemical black oxide, magnetite steel, Iconel™ or any of your precious metals such as silver or gold.

7649

With these latter, it really is helpful to use the Loctite SF 7649 activatorbefore applying the threadlocker, to activate the surface and enable the adhesive to achieve the full strength quicker.

Loctite SF 7649 has drying time of 30-70 seconds. However, it has on-part life of 30 days, which means you can spray it on your parts ahead of time in a separate phase of your process and have them ready to be built in when the time for that comes.

To summarize what the activator does:

When to use activator_temp_gaps_deep thrds

  • Shortens the cure time on any type of metal
  • Activates the inactive surfaces to promote adhesion
  • Promotes adhesion in cold temperatures
  • Promotes curing / adhesion where there are larger gaps or deep threads

Feel free to visit our website for more information on Loctite Threadlockers (you can select a different language or country in the navigation at the top of the page).

Why is Loctite Threadlocker better than double nut

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Coming back to mechanical locking devices for threaded assemblies, double nut is probably the most common one. Wherever the assembly design allows it, it’s the simplest thing to do: just add one more nut of the same size you already have anyway for the bolt in question.

While the second nut does increase the surface of interfaced threads, it doesn’t eliminate the gaps between them. Certainly, you can argue that it will take that much longer for the vibrational impact to shake such a bolt into loosening, but the loosening will still inevitably happen.

Additional nut increases one more thing: it doubles the amount of surface that can corrode together between the bolt and the nuts. And that’s a nasty surprise that you normally discover when you’re about to dismantle the piece.

Finally, out of all the mechanical locking devices, the nuts are the heaviest, and if you use several double nuts to secure your bolts on a piece of equipment, you definitely have to count with all the additional weight you’ve added to it. As far as elegant solutions go, this is not one of them.

If you replace the second nut by just a few drops of a Loctite Threadlocker, you’ve not only found a much more elegant solution, but you’ve really resolved the issue of vibrational loosening – permanently.