Engage Partner to Make Cleaning Part of Medical Device Offering

In our previous post we discussed the serious, even catastrophic consequences contamination can cause. Medical device manufacturers –from small machine shops to large corporations – need to establish protocols that enable them to consistently deliver clean components and meet regulatory standards.

According to the Institute of Validation Technology, the FDA, in its Quality System Regulations, states that each manufacturer must “establish and maintain procedures to prevent contamination of product by substances that could be expected to have an adverse effect on product quality.”

The FDA also requires medical device manufacturers to establish “documented cleanliness requirements.”

Beyond Your Core Competencies?

If you are like many precision manufacturers, you have deep expertise in producing machined and/or plastic molded parts to strict tolerances. However, cleaning those parts and documenting your decontamination procedures may be outside your core competencies. For that reason, many device manufacturers turn to specialty partners like PTI Industries for their cleaning and validation. Doing so enables manufacturers to meet industry requirements while eliminating costly equipment purchases, staff training, and numerous certification requirements.

With PTI Industries, you produce your parts, we clean and test* them, and then you take care of packaging and distribution. Together, we get your products to market quicker while allowing you to save time and money.

*Note: PTI does not test for Endotoxin

Specialized Services for the Medical Industry

PTI Industries offers several special cleaning and testing processes for the medical device industry, including:

Precision Cleaning and Cleanliness Testing: Ensures you have a documented and repeatable cleaning process to deliver results that exceed industry standards. Trained experts help to determine which precision cleaning process will produce the best outcomes, based on your components.

Passivation: Stainless steel is naturally corrosion-resistant; however, it becomes contaminated when subsequent forming and machining operations are performed that introduce free iron particles and other surface contaminants. Passivation treats stainless steel with a mild oxidant, such as citric acid solution, to remove surface contamination and enhance the spontaneous formation of a protective passive film on the steel’s surface.

Non-Destructive Testing: With the increasing demand for parts made to stricter tolerances, the use of non-destructive testing has become an integral part of the manufacturing process. Non-destructive testing confirms that parts have been produced without defects and ensures they will perform as expected.

Save time and eliminate potentially damaging results by outsourcing your precision cleaning and testing to PTI Industries. Together, we can determine solutions to help ensure the success of your medical device manufacturing process.

Inside the Nondestructive Testing Department

Of all the services PTI Industries provides, NDT (nondestructive testing) is one of the most important. Checking for the integrity of a part, whether you coat it or paint it later on, is critical to part performance. NDT testing checks for discontinuities or defects that could have occurred during any part of the production process, including casting, welding, or forging.

When a part comes in for NDT, it’s inspected for flaws and weaknesses without damaging the part in any way. “If 1,000 parts arrive, then 1,000 parts are tested and given 110% inspection,” said Mat Burke, Manager of NDT, Shot Peen, Coatings and Shipping. PTI doesn’t typically test for samples unless this is specifically agreed upon.

A Typical Day in the NDT Department

The NDT department tests and inspects anywhere from 3,500 to 5,000 parts a day and averages 50,000 parts a month. Because PTI specializes in multi-process services, the majority of parts that arrive for nondestructive testing also receive other special processes. Only 12-15% of the parts that come through the NDT department don’t arrive from another department. Before reaching NDT, most parts receive services including passivation, dry film lubrication, and precision cleaning.

According to Burke, when working with customers it’s essential to be flexible without jeopardizing the integrity of the part. The NDT department is often a part’s last stop in multiple special processes. “A customer sends in an order for three processes that was quoted for eight days, but they want it in three days.  We pull this off on a regular basis,” Burke said.

Two Operating Sides for Two Critical Testing Methods

The NDT department is divided down the middle, with established incoming and outgoing areas. The left side of the room is set up for FPI (fluorescent penetrant inspection), also known as liquid penetrant inspection (LPI), and is run like an assembly line with tables holding penetrant well tanks.

Nonmagnetic parts are tested for defects using liquid penetrants as they are passed through one of two different defect sensitivity levels. A visible dye penetrant for lower sensitivities uses a white light and fluorescent penetrants for higher sensitivities uses ultraviolet light. Accurate results require thorough pre-cleaning decontamination, correct soak time, proper penetrant removal, followed by drying in a convection oven using a developer bleed-out.

On the right side of the department the MPT (magnetic particle inspection) section houses two individual machines. All MPT testing is done inside a solo machine to determine if any defects are present using calculated data that includes strength of current and direction of magnetic field.

MPI is a nondestructive testing method used on material that can be magnetized, or a ferromagnetic material such as cobalt, iron, nickel, or certain alloys. During the MPI process, small magnetic particles are attracted to any defects on or near the part’s surface. Demagnetization of the part follows, using special equipment to reverse the magnetic field and safeguard future machining and welding of the part, as well as your electronic equipment.

Test parameters and techniques are defined as parts arrive. Any fixtures and tools that are needed for the completion of NDT testing are completed in-house. Heavier parts, for example, could mean designing a hoist system to lift and move the components.

Qualified NDT Technicians

Certified technicians who are qualified based on the required level of training perform all the nondestructive testing and inspection. Training begins as an entry-level trainee before moving on to Level 1. Level 1 becomes a Level 2 technician and qualifies to inspect parts after meeting the required time of over 400 to 500 hours. To be a Level 3 technician, a minimum of four years in one discipline must be fulfilled, or eight years total to be qualified for both FPI and MPI.
All the training is done in-house, guaranteeing a more detailed instruction that ensures competent and fully qualified specialists for every NDT job. PTI’s Level 3 technician has over thirty years of experience and is designated a Responsible Level 3 because he oversees and is responsible for all the training, testing, and inspecting in the NDT department.

How Can Four Equal One? – A Case Study in Streamlining Multiple Special Processes

blog-pic-41pti-300x245In a previous post we spoke about streamlining your special processes to improve your bottom line. Now we’ll take a look at how one part would move through our multi-process shop. Four processes can equal one when a part has four sequential special processes done in one shop on one purchase order. To illustrate this, let’s look at a section of the value stream map for a Locking Nut that mates up to an LPT Shaft, which ultimately ends up in a jet engine.

This life limited part starts out as a 410 stainless steel bar. After machining and heat-treating, we receive the part in to perform Magnetic Particle Inspection (MPI) which is a form of Non-Destructive Testing. This special process is done to ensure there are no cracks or voids in the parent material that could result in an in-flight failure.

Having passed MPI, the part travels immediately into our Dry Film Lubricant (DFL) Department, where it has a thin layer of Molybdeum Disulfide (a type of DFL) applied to its threads. This ensures it will rotate smoothly when mated up to an LPT shaft at assembly.

Next, the part moves right into our Bonded Products Division where a special low-friction fabric washer that we laser cut to exacting tolerances is adhered to its bearing surface using our Adhesive Bonding technology.

This special fiber washer acts as a maintenance-free thrust bearing when it mates up to the adjoining surface on the LPT shaft.

The final stop for this part is in our Precision Cleaning Division. Here it will undergo a thorough cleaning and inspection to a microscopic level to ensure there are no particles on it that could damage the part itself or other sensitive components within the engine during use.

It is PTI’s unique Multi-Process capabilities that make it possible for Four to equal One. Streamlining your processes in our shop will result in reduced shipping, handling, paperwork, downtime and all related peripheral activities that will save you money in the long run.

Magnetic Particle Inspection

When looking for a reliable, economical testing method for detecting flaws and discontinuities in your magnetic parts without damaging the part in any way, a preferred method is magnetic particle inspection (MPI).

MPI is a nondestructive test method that detects linear, surface, and near-surface flaws in material that can be magnetized, or ferromagnetic material, such as cobalt, iron, nickel, or certain alloys. During MPI, small magnetic, iron particles are attracted to any defects on or near the surface of your parts.

Applications for magnetic particle inspection include many different industries, including automotive, power generation, medical device, and aerospace industries. Testing is done on a variety of product forms and at almost any stage in the component’s production cycle, including castings, forgings, and weldments.

MPI advantages include:

  • Quick and simple application
  • Ability to detect defects through thin coatings
  • Highly sensitive to surface and slightly subsurface flaws that will appear on the test part
  • Easy automation and high-volume production testing
  • Less costly than other quality assurance testing methods

Limitations to MPI are:

  • Part material must be magnetic
  • Limited detection for subsurface indications
  • The direction of the magnetic field must be accurate
  • Complex test parts sometimes pose difficulty with magnetic properties
  • Demagnetization is often required

Your parts are tested for defects on our wet horizontal machines following these basic steps:

  1. Surface preparation: Your part is cleaned of grease, oil, moisture, and other contaminants. PTI uses TriChloroethylene Vapor Degreasing, also used with the FPI method.
  2. Determine magnetic properties: Calculations are done to know the amount of current required to magnetize your part. Both the adequate strength and correct direction of magnetic field must be used.
  3. Magnetize component: Your part is magnetized with a magnetizing pulse that is applied in short bursts of a half second to improve particle mobility. It is then bathed with a light oil containing small iron particles which will line up along any defect.
  4. Visual inspection: A UV black light is used to look for defects that will create a leakage field. The iron particles will cluster at any flux leakage point, forming a visible indication to an otherwise undetectable defect.
  5. Subsurface flaw detection: Unlike FPI, MPI can show defects below the surface such as voids in a casting. Indications will lose definition as flaw depth increases.
  6. Demagnetize component: Special equipment that operates in the opposite manner of magnetizing equipment is used to reverse the magnetic field. Remaining magnetic fields can adversely affect machining and welding, and interfere with electronic equipment. Test oil is then removed by vapor degreasing.

PTI gives you multiple solutions to your special processes in one stop. In addition to our Nondestructive Testing, we offer Precision Cleaning, Shot Peen, and Adhesive Bonding.

This is the fourth (and final) in a series providing detailed information on the special processes provided by PTI.
Part One: Dry Film Lubrication Gives Critical Long-Term Protection
Part Two: Get Quality Control for Your Parts with Nondestructive Testing
Part Three: Liquid Penetrant Inspection Is Economical and Versatile

Liquid Penetrant Inspection Is Economical and Versatile

FPI-1024x746_cropped-300x219Liquid Penetrant Inspection is a nondestructive testing method used to reveal surface discontinuities by bleeding out a colored or fluorescent dye from the flaw. This process is called capillary action, where a liquid is drawn into a clean, dry defect through low surface tension.

Liquid Penetrant Inspection (LPI), also known as Fluorescent Penetrant Inspection (FPI), is one of the two most common nondestructive testing methods, a process that tests for discontinuities without damaging parts in any way. The other method is Magnetic Particle Inspection (MPI), which is limited for use on magnetic parts.

If your parts are nonmagnetic, the only option is Liquid Penetrant Inspection. It relies on using either an ultraviolet light for a fluorescent liquid penetrant, or a white light for a visible dye penetrant.

The two penetrants are classified by their sensitivity levels. Visible penetrant is red in color and represents the lowest sensitivity. Fluorescent penetrants are yellow-green and contrast with the darkened environment, representing the highest sensitivity to defects.

Liquid Penetrant Inspection and Fluorescent Penetrant Inspection consist of 6 steps:

  1. Pre-cleaning the part to be free of all dirt, oil, grease, paint, rust, or any loose scale that could prevent the liquid from penetrating the defect or cause false indications. For most parts, PTI uses vapor degreasing with TriChloroethylene. Solvents such as MEK or Acetone are used to clean Titanium parts where Tri-Chlor may have adverse effects. Any defects present must be open to the surface, dry, and free of contamination.
  2. Application of penetrant to the part’s surface has a dwell or soak time that allows the penetrant to permeate into any cracks and voids. The dwell time can be from 5 to 30 minutes, depending on the material of the part and the size of the potential flaws. Smaller defects require a longer penetration time.
  3. Excess penetrant is removed from the part’s surface. This prevents the possibility of masking defects from the developer by leaving a background. Without proper removal, false indications may also occur. PTI generally uses water to wash the penetrant off.
  4. Application of developer follows drying time in a convection oven. A thin, light coating of developer is sprayed on the part and a dwell time is again observed. The developer draws the penetrant out, creating a visible indication or flaw in the developer known as a bleed-out.
  5. The part is inspected using visible light on a visible dye penetrant, typically with an intensity of 100 foot-candles or 1100 lux. Ultraviolet or black light is used for fluorescent penetrant examinations. The correct length of time is critical. The length of an indication can increase with time as the penetrant bleeds out, causing an acceptable indication to become an unacceptable defect.
  6. Post cleaning of parts with water to remove all developer, and thorough drying after evaluation.

Liquid penetrant advantages include:

  • High sensitivity to small surface discontinuities.
  • Indications can reveal relative size and shape of the flaw.
  • Parts with complex shapes can be routinely inspected.
  • Few limitations to part materials, i.e., metallic and nonmetallic, magnetic and nonmagnetic, conductive and nonconductive materials may be inspected.
  • Inexpensive and fast inspection of large volumes and large areas of parts.
  • Visual representations of flaws are made on the part surface.
  • Portable and convenient process.

Primary disadvantages of liquid dye penetrant are:

  • Flaws must be open to the surface for detection.
  • Part surface must be accessible for examination.
  • Part material with porous surfaces can’t be inspected with LPI.
  • The part surface must be clean of all contaminants that could mask defects, including removal of any metal from wire brushing, shot blasting, or grit blasting.
  • Surface finish must be smooth before inspection, which could require grinding.
  • Proper chemical handling and disposal is necessary.

PTI offers both Liquid Penetrant Testing and Fluorescent Penetrant Inspection as a valuable tool during new construction and in-service inspections.

This is the third in a series providing detailed information on the special processes provided by PTI.

Part One: Dry Film Lubrication Gives Critical Long-Term Protection
Part Two: Get Quality Control for Your Parts with Nondestructive Testing
Part Four: Magnetic Particle Inspection

Get Quality Control for Your Parts with Nondestructive Testing

FPI-Dwell-1024x637-cropped-300x239Nondestructive Testing (NDT) is an indispensable cost-saving technique for your quality control process. Modern nondestructive tests are used to control manufacturing processes, lower production costs, maintain consistent quality, and ensure product reliability.

NDT determines the integrity of your parts without causing harm or damage to the test part. Tests that use destructive methods can only be done on a limited number of samples, whereas with NDT inspection, your parts can be put into service without fear of part failure.

NDT is the process of inspecting, testing, or evaluating your components for discontinuities and differences in material characteristics. Physical properties can also be measured, such as impact resistance, ductility, yield, tensile strength, fracture toughness, and fatigue strength.

The detection of flaws may involve cracks or inclusions in the welding and castings, or any structural variations that can lead to decline in strength and possible service failure. If your parts undergo conditions such as repetitive forces, extended wear, extreme loads, and high speed operation, nondestructive testing to monitor serviceability is a critical requirement.

PTI performs two methods of NDT to check for cracks or indications:

  • Magnetic Particle Testing (MPT)
    This type of testing is used for materials that can be easily magnetized, such as iron, nickel, cobalt, and some of their alloys. Powerful magnetic fields are concentrated and applied to the material, detecting surface and slightly subsurface flaws.
  • Liquid Penetrant Testing (LPT), also called Fluorescent Penetrant Inspection (FPI)
    This method can be used for non-porous, non-magnetic materials for the detection of surface discontinuities. A visible dye is applied to the part surface and discontinuities are detected using ultraviolet or fluorescent light.

Applications for NDT include aerospace engines and airframes, orthopedic and analytical equipment for medical devices, automotive, power generation, laser components, and heat exchangers. NDT can be used during the manufacture and service of your parts, assessing quality and assuring safe operation.

As the demand for product reliability and safety grows, NDT and other special processes must meet more stringent requirements. PTI provides one-stop, special processes for all your manufacturing needs, including Precision Cleaning, Dry Film Lubrication, Adhesive Bonding, and more.

This is the second in a series providing detailed information on the special processes provided by PTI.

Part One: Dry Film Lubrication Gives Critical Long-Term Protection
Part Three: Liquid Penetrant Inspection Is Economical and Versatile
Part Four: Magnetic Particle Inspection