Clean Machined Parts with an Ultrasonic Cleaner

How To Efficiently Clean Machined Parts

Elma Select Ultrasonic Cleaner
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Whether you’re running a CNC shop, fabricating components for aerospace, or maintaining equipment on the production line, clean machined parts are essential for performance, durability, and downstream processes like coating or assembly. Contaminants such as cutting fluids, metal fines, and oxidation not only affect part quality — they can also lead to failed inspections and costly rework.

Industrial manufacturers have several cleaning options at their disposal. In this post, we’ll walk through three of the most effective methods for cleaning machined parts, with a focus on ultrasonic cleaning — a highly efficient solution for precision results. We’ll also compare it to other common methods so you can make the best choice for your facility.


Why Cleaning Machined Parts Is Critical

Before we dive into methods, let’s talk about why cleanliness matters. Machining operations leave behind a mix of contaminants:

  • Coolants and lubricants
  • Metal chips and fines
  • Oxidation or corrosion products
  • Dust, dirt, or polishing residues

Leaving these residues in place can lead to poor fit during assembly, impaired surface treatments (like plating or painting), and even premature component failure. Cleanliness is often a specification requirement in aerospace, automotive, and medical manufacturing.

That’s why finding the right method to clean machined parts is a critical part of your workflow — not an afterthought.


1. Ultrasonic Cleaning: The Fast, Thorough Solution for Precision Parts

For many industrial operations, ultrasonic cleaning is the go-to solution — and for good reason. It’s fast, thorough, and can clean complex geometries that brushes or sprays can’t reach.

How It Works

Ultrasonic cleaners use high-frequency sound waves (usually in the 25–80 kHz range) transmitted through a cleaning solution. These sound waves create microscopic bubbles in a process called cavitation. When the bubbles collapse, they generate intense localized pressure and temperature — dislodging contaminants from the surface and even from blind holes, threads, and internal channels.

Key Benefits

  • Deep, uniform cleaning of parts with intricate geometries
  • Non-damaging, ideal for delicate or tight-tolerance components
  • Can be used with aqueous or solvent-based solutions
  • Reduces the need for manual scrubbing or multi-step processes
  • Fast cycle times (often under 15 minutes)

Best Applications

Ultrasonic cleaning is especially useful for:

  • Fuel injectors, valves, and aerospace components
  • Medical or dental instruments
  • Parts with fine threads, small holes, or complex internal passages
  • Precision assemblies prior to coating or bonding

If you’re dealing with parts that demand spotless surfaces and a non-abrasive process, ultrasonic cleaning delivers consistent, repeatable results.

We often speak with customers using solvents to remove oil and grease from metal parts. They don’t realize that water-based formulations have been improved to the extent that solvent cleaning is no longer necessary. There are significant advantages to switching to ultrasonic cleaning with water-based soaps instead of manual cleaning with toxic, flammable solvents.


2. Aqueous Parts Washing: A Reliable Workhorse

Another popular option for cleaning machined parts is aqueous parts washing — typically using a water-based cleaning solution combined with agitation, heat, and sometimes spraying.

How It Works

Parts washers come in various configurations: manual spray cabinets, automated conveyor systems, and immersion tanks with agitation or rotating baskets. Most systems use a heated alkaline detergent to break down oils, greases, and particulates.

Pros and Cons

Cost-effective and easy to operate
✅ Suitable for larger parts or high-throughput needs
✅ Available in automated formats for production lines

❌ May struggle with tight geometries or blind holes
❌ Not as effective for fine or delicate components
❌ Requires drying cycle and regular solution maintenance

Best Applications

Aqueous parts washing is ideal for general-purpose cleaning of:

  • Castings and housings
  • Brackets, gears, or frames
  • Heavily soiled or oily components

If you’re cleaning bulky or rugged parts with less concern about fine detail, this method is often sufficient — and budget-friendly.


3. Solvent Cleaning: Targeted Use for Stubborn Contaminants

Solvent cleaning has been used for decades to remove grease, oils, and certain residues that water-based systems can’t dissolve. While it’s less common today due to environmental and safety concerns, solvent cleaning still plays a role in specific use cases.

Applications that require solvent-based cleaning are often government regulated processes that specify the use of solvents.  For example, if the FDA approved a process to clean a medical device with solvent, it’s very difficult and time consuming to change that approved process.  Although a customer may be aware that switching to a water-based process would be safer and easier, it’s just too much trouble to make the change. 

How It Works

Parts are either wiped, immersed, or sprayed with a chemical solvent designed to dissolve specific contaminants. In some facilities, vapor degreasing units are used to apply and recycle solvent vapors in a controlled environment.

Pros and Cons

Effective for hydrocarbon-based residues
✅ Can clean without water exposure (important for sensitive parts)
✅ Often used as a pre-treatment for coatings

Health, safety, and environmental concerns
❌ Requires proper ventilation and PPE
❌ Solvent disposal must meet regulatory standards

Best Applications

Solvent cleaning is typically reserved for:

  • Parts with coatings or oxidation that require chemical stripping
  • Small batches where water use is impractical
  • Pre-cleaning before plating or painting

Solvent cleaning can be highly effective — but it’s best used selectively and with full awareness of safety protocols.


Choosing the Right Method to Clean Machined Parts

When evaluating cleaning methods, it’s important to match the process to the part requirements, contaminants, and throughput needs. Here’s a quick comparison:

MethodBest ForNot Ideal For
UltrasonicSmall, complex, precision partsExtremely large parts
Aqueous WashersGeneral-purpose and large partsVery fine or intricate features
Solvent CleaningHeavy oils, selective strippingHigh-volume or eco-sensitive ops

In many industrial settings, these methods are even used in combination — for example, pre-washing in an aqueous spray system followed by a final ultrasonic clean.


Final Thoughts

No matter your industry, ensuring clean machined parts is essential to performance, product quality, and compliance. While there’s no one-size-fits-all solution, ultrasonic cleaning stands out for its ability to remove microscopic contaminants from even the most complex parts — safely and efficiently.

If you’re unsure which system is best for your application, the experts at Tovatech are here to help. Whether you need help selecting an ultrasonic cleaner or designing a complete cleaning workflow, give us a call or start a chat — we’re ready to guide you to the right solution.

About Bob Sandor

Bob began working as a chemist in 1987 and remains a science geek to this day. After his PhD he worked on the bench in materials and inorganic chemistry for 10 years. He then took on a love for marketing and sales. He combined his passion for science and business and took entrepreneur general management positions in large corporations like Hoecsht Celanese now Sanofi Aventis, Bel-Art and Smiths Detection. There he learned what it would take to run a business and finally Tovatech was co-founded in 2006. Bob’s hobbies include playing, listening and composing music, skiing, working out, the internet and all things science. Read More