Lubricants are essential to increase a plastic part’s lifespan. Today, I’m going to write a detailed piece on choosing the best lubricant for plastic components.
How to Choose the Right Plastic Lubricant?
Plastic lubricants are essential for greasing or polishing plastic parts to increase their life and reduce power consumption and friction. When choosing a lubricant, the most crucial factor is how compatible it is with the plastic part. Research studies have consistently shown lubricating plastic sliding bearings can increase their life span by four to five times.
Lubricants based on silicone, perfluorinated PFAE, synthetic hydrocarbons (SHC or PAO), and mineral oils generally work nicely with plastics. Esters and polyglycols are generally not compatible with plastic, although there are exceptions based on the type of plastic material.
How to Figure Out the Compatibility of Plastic Parts and Lubricants?
To determine the compatibility between lubricants and plastics, the best way is to observe the changes in the physical properties of plastic material under conditions such as environment, speed, and load. Manufacturers should closely monitor the changes in hardness, strength, elongation, weight, and volume.
Another important aspect of determining consists of reflecting on your work’s worst possible scenarios while conducting tests because both lubricant and plastic material will be under high temperatures and adverse environments, which will make them change in certain ways.
Choosing an unsuitable lubricant or grease will have a severe effect on plastic parts. Stress-cracking, discoloration, warpage, and losing structural integrity are common scenarios when such mistakes happen.
Criteria for Choosing Best Lubricants for Plastic Parts
There are three important criteria to follow for choosing a plastic lubricant:
- Aging Resistance
High viscosity chemicals are the best option as lubricants as they give good protection to plastic parts against cracks, piercing, or otherwise any adverse effects. Higher loads would need oils with higher viscosity oils to sustain a lubricant film from start to top; on the other hand, lighter loads require lower viscosity oils to prevent any drag.
A plastic part’s compatibility with lubricants is very much dependent on its chemical structure. The lubricants which work best with plastics are based on perfluorinated PFAE, mineral oils, synthetic hydrocarbons (SHC or PAO), and silicone. Lubricants made from esters and polyglycols are not suitable for most plastics.
Mixing additives with plastic materials can also lead to an unplanned reaction between the lubricant and plastic. The type of additives being used completely determines the effects. Rigid additives like molybdenum and graphite can pierce and weaken a plastic part; however, PTFE additives, even after having the same rigidness, can be very advantageous in certain cases by providing dry lubrication.
3. Aging Resistance:
Lubricants are highly likely to affect plastic parts as they age. That’s why synthetic lubricants are the best choice for marinating the plastic part for a longer period of time. The key to keeping the plastic in good shape for a longer period of time is to stay away from outgassing byproducts of plastic, specifically formaldehyde and styrene.
Without any doubt, the best lubricant for plastic is one that is mineral-oil-based. They give a fantastic performance in typical plastic applications, and most importantly, they don’t attack plastic materials.
However, with the growing trend of rapid prototyping, higher temperatures, longer operations, and faster cycle times, companies are more interested in synthetic lubricants – The best example is hydrocarbon-based lubricants. They offer excellent compatibility with most plastics, good aging resistance, and great long-term lubrication in a temperature range of -51 – 150°C.
Another approachable option is PFAE lubricants. These lubricants are known to provide fabulous compatibility even with plastics considered difficult to match. The ability to provide a good blend between adhesion and plastic surface wetting makes it a prime choice for all lubricants. They are most useful in elevated temperature operations – up to 260°C. The only drawback I find is the high cost. Utilize PFAE oils only when it’s a necessity.
For low-load applications, one should consider silicone-based lubricants. The lubricants can bring a lot to the table, like great compatibility and a wide working temperature range of – -67-218°C.
What About Lubricating Plastic Gears?
Like any other plastic pat, plastic gears also need sufficient lubrication for smooth momentum. The importance of lubricating ears can be best understood when they work without being a lubricant for a prolonged time. When a set of gear teeth comes into contact, the point of contact experiences compressive pressure and moves as the gear turns. After sustained repetitions and compressive stress, the plastic material can undergo certain issues, such as:
- Increased friction
- Heat generation
- Exposed surface asymmetry
- Wearing down the external surface
- Increase in force needed to move the gear
Anyone who has worked with plastic gears would realize its importance for making the gears faster, smoother, and even more resistant to damage. however as gears are made to be used without lubricants, special attention needs to be given to do’s and don’ts while doing the lubrication process.
Lubricating materials silicone, PTFE, and graphite are prime choices are plastic gear’s internal lubrication.
The most important factors to conder while choosing lubricants should be chemical compatibility, thermal stability, outstanding lubricity, and compatible viscosity.
Fascinating Read – What is PVDF (Polyvinylidene Fluoride) | A Detailed Guide
Below are the frequently added questions on a lubricant for plastic. Let’s dig deep to know more.
Is it necessary to grease or lubricate plastic gears?
Lubricating or greasing isn’t always necessary. Most plastic gears can run without any kind of lubrication; however, using the right lubrication can readily increase its life expectancy and prevent cracks.
Can vaseline be used as a lubricant?
Vaseline or petroleum jelly is compatible with plastics but won’t give ideal results. Even if you go with it checking its chemical compatibility with plastic is advised.
What is Teflon grease?
Teflon grease is comprised of PTFE and can be used in most plastic parts. The presence of PTFE ensures a formation of a dry film and avoids solid containments.
How to lubricate plastic wheels?
For lubricating plastic wheels, a PTFE spray will be perfect. It’s easily available and manufactured by many brands.
Is Silicone Spray a dry lubricant?
It is not a dry lubricant and shouldn’t be used here; pressure and load-bearing are involved.
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That was my take on the best lubricants for plastic parts. I believe choosing a lubricant for the plastic part is a critical part of doing the job. Do it well, and you can increase a plastic part’s life expectancy substantially.
Kindly share your review in the comment box.
Have a wonderful day.