A discussion with the plastics pros at AIP on how the ISO 13485:2016 standard improves quality assurance for medical machined plastics.

 

What sets a quality management system (QMS) above the rest for medical device manufacturing and machining? Safety, sanitation and product integrity are, without a doubt, crucial for any plastics machining company working with materials for medical use.

 

How can you ascertain the validity of a company’s QMS?

 

One way to do this is to look for whether the machining shop is ISO 13485:2016 certified. This regulation requires that a certified organization demonstrate that their QMS is effectively implemented and maintained.

 

At AIP, we not only promise a quality assurance program, we are ISO 13485:2016 certified. As a precision plastics machining company, we have worked with medical OEMs to develop parts for critical medical devices for more than 35 years. We understand the value of a transparent QMS program through the ISO 13485:2016 certification.

 

If you are curious to know more about this certification, read on as we discuss more on the benefits of the ISO 13485:2016 certification.

 

What is the ISO 13485:2016 Standard?

 

The ISO 13485:2016 standard specifies requirements for a quality management system where an organization or company must demonstrate its ability to provide medical devices and related services that consistently meet customer and applicable regulatory requirements, such as sanitation in the work environment to ensure product safety.

It encompasses a broad range of organizations involved in the medical device industry. These include: design and development, production, storage and distribution, installation, or servicing of a medical device and associated activities.

 

How does this certification help AIP serve the medical market?

ISO 13485:2016 reflects our strong commitment to continual improvement and gives customers confidence in our ability to bring safe and effective products to the medical market.

 

We know that product durability and cleanliness are not just desirable within the medical industry, they’re essential. The ISO 13485:2016 compliance highlights our commitment to machining medical devices with quality custom plastic components.

 

We have been successfully audited by some of the most stringent OEMs in the orthopaedic and medical device industries. Our plastics are processed with strict hygienic procedures to ensure the highest level of sanitation down to the sub-molecular level.

 

At AIP, quality assurance is a norm not only for our customers but for ourselves. The ISO 13485:2016 certification is designed to integrate with our existing quality management system. With it, we can ensure our customers the highest-level of safety and performance for their medical machined parts.

 

What about AIP Precision Machining allows us to achieve ISO 13485:2016 certification?

 
“Anyone who tells you that it is not about the people is wrong,” said MacDonald. “While leadership provided the vision and desire to seek out ISO 13485:2016 certification, our dedicated team at AIP went the distance and got us over the finish line. It is our team who will maintain and continually enhance those key processes to make us better every day at meeting the needs of our valued customers.

 

Want to learn more about machining plastics for medical devices?

Read our blog on ways to ensure sterilization in plastic machined medical applications:

 

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An Informational Brief on Polymer Machining

 

Since it was first polymerized in 1954 by Karl Rehn and Giulio Natta, polypropylene (PP) has become one of the leading polymer choices for a wide array of applications from automotive to commercial to medical.

 

Polypropylene plays a significant role in medical applications due to its high chemical resistance, lightweight, radiolucency and repeated autoclavability. Furthermore, medical grade PP exhibits good resistance to steam sterilization and moisture resistance. Disposable syringes, instrument or implant caddies and fluid delivery systems are the most common medical application of polypropylene. Other applications include medical vials, diagnostic devices, petri dishes, intravenous bottles, specimen bottles and surgical trays.

 

Want to learn more about the polymers we precision machine for medical applications?

 

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AIP has over 35 years of experience machining complex components from thermoplastics like polypropylene. In this insightful technical brief, we will discuss what goes into machining polypropylene and how it differs from other manufacturing options such as metal machining, injection molding, and 3D printing.

 

Homopolymer vs Copolymer – What’s the Difference?

 

The two main types of polypropylene available on the market are homopolymers and copolymers. Although they share many properties, there are some differences that help guide machinists and engineers in choosing the right material for their PP application. For the purposes of this blog, we will briefly review the differences between PP homopolymer and PP copolymer.

 

PP HomopolymerPP Copolymer
  • High strength to weight ratio and stiffer & stronger than copolymer
  • Good chemical resistance and weldability
  • Good processability
  • Good impact resistance
  • Good stiffness
  • Food contact acceptable
  • Suitable for corrosion resistant structures
  • Bit softer but has better impact strength; tougher and more durable than homopolymer
  • Better stress crack resistance and low temperature toughness
  • High processability
  • High impact resistance
  • High toughness
  • Not preferable for food contact applications

 

Properties of Polypropylene

 

Keeping information about the properties of a thermoplastic beforehand is always beneficial. This helps in selecting the right thermoplastic for an application. It also assists in evaluating if the end use requirement would be fulfilled or not. Here are some of the key properties of polypropylene:

 

Polypropylene is characterized by excellent chemical resistance in corrosive environments, resistance to cleaning agents and solvents and by a high heat deflection temperature.

 

It also has great dimensional stability and is fairly easy to machine. As noted above, it is available in heat-stabilized homopolymer and copolymer grades. At AIP, we machine POLYSTONE P, PROPYLUX HS and HS2, PROTEUS LSG HS PP from MCAM, TECAPRO MT and TECAFINE PP from Ensinger. Interesting to note is that both the PROPYLUX and TECAPRO heat stabilized PP grades are available in both standard and custom colors for medical sorting and sizing organization. Whatever your application, our machinists can help you in material selection, sizing and manufacturing techniques from concept to completion.

 

Melting Point of Polypropylene – The melting point of polypropylene occurs at a range.

 

Homopolymer: 160 – 165°C
Copolymer: 135 – 159°C

 

Density of Polypropylene – PP is one of the lightest polymers among all commodity plastics. This feature makes it a suitable option for lightweight\weight saving applications.

 

Homopolymer: 0.904 – 0.908 g/cm3
Random Copolymer: 0.904 – 0.908 g/cm3
Impact Copolymer: 0.898 – 0.900 g/cm3

 

Machining Polyproylene

 

Annealing Polypropylene

Due to its low annealing temperature, PP, like any polymer under heat and pressure, has a tendency to deform during machining. The annealing process at AIP greatly reduces the chances of these stresses occurring from the heat generated during machining PP and other polymers. Our machinists use computer controlled annealing ovens for the highest quality precision machining.

 

Machining Polypropylene

As a part of the polyolefin family, PP is semi-crystalline, which means that it can be machined at tight tolerances. We recommend non-aromatic, water-soluble coolants because they are most suitable for ideal surface finishes and close tolerances.

 

Bear in mind that polypropylene has variable levels of thermal expansion and will move a great deal with slight temperature changes. Some examples are pressurized air and spray mists. Coolants have the additional benefit of extending tool life as well.

 

Some companies machine both metals and plastics, which has detrimental outcomes for clients. Many past experiences have shown parts going to customer without cracks, only to develop cracks over time due to exposure to metal machine shop fluids. Be sure to use a facility like AIP that only machines polymers.

 

Preventing Contamination

Contamination is a serious concern when machining polymer components for technically demanding industries such as aerospace and medical sciences. To ensure the highest level of sanitation down to the sub-molecular level, AIP Precision Machining designs, heat-treats, and machines only plastics with any sub-manufactured metalwork processed outside our facility. This allows us to de-risk the process from metallic cross contamination.

 

Polypropylene Machining Guide: Supportive Information

 

ISO 13485:2016 Certification
ISO 9001:2015 Certification

 

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A discussion with the plastics pros at AIP on how to choose the right plastic for your medical application

 

When it comes to selecting a polymer for a medical application, there are a myriad of factors that play into deciding which grade of polymer is the best candidate. Of course, the number one concern in medical device design is safety of human life.

 

For this reason, trends in medical device design are moving toward miniaturization and portability. Additionally, sterilization and cleanliness continue to lead design considerations globally, requiring devices to withstand a range of chemicals and sterilization techniques.

 

As a precision plastics machining company, AIP has over 35+ years of experience working with medical OEMs to develop parts for critical medical devices. In this issue of our monthly blog, we will discuss what makes a polymer medical grade and how to choose the right polymer for a medical device application.

 

What are medical grade plastics?

 

Let’s begin with what a medical grade plastic is. Medical-grade plastics refer to plastics used to make medical products, products for in vitro diagnostics and primary packaging for pharmaceuticals.

 

Most importantly, plastics used in the medical field are coming in contact with human tissue, fluids, chemicals, drugs and many more substances. There are literally thousands of medical applications from packaging to spinal implants. Based on this information, your supplier should be familiar with the types of polymers and composites you need machined. They should additionally know the best machining process for your application. That’s why design conception is crucial as the first step.

 

1. Design requirements and constraints

 

First and foremost, what is the function of the polymer for the device?

 

Your machine shop should be asking you in depth questions about your medical application. Questions to consider include:

 

  • Should the material be biocompatible?
  • Is the product for single use?
  • Will the component undergo sterilization? If so, which method?
  • Does color and aesthetics matter in the machining process?
  • Is UV resistance needed?
  • What tolerances must be met for temperature, wear, impact, etc?

 

The following material selection flow-chart displays the overall process of developing a medical grade plastic part or device:

 

 

2. Industry Standards

 

What industry standards and regulations control the production of the material?

 

At AIP, our plastics are processed with strict hygienic procedures to ensure the highest level of sanitation. Make sure that your machining company is compliant and/or registered with the appropriate regulatory organizations. Some common medical certifications include the following:

 

  • ISO 10993
  • ISO 13485:2016
  • FDA Registered

 

3. Biocompatibility

 

How long does the component need to be in contact with the human body or tissue?

 

There are three categories of contact duration if a component is subject to body tissue or fluid:

 

  • Short-term contact (Less than 24 hours)
  • Medium term contact (Between 1-30 days)
  • Long-term or Permanent contact (Greater than 30 days)

 

4. Sterilization/Cleanliness

 

Will the device need to be resistant to chemicals or undergo multiple sterilizations?

 

Whether it’s a feeding tube, a drug delivery device or a surgical implant, the polymer material must be able to withstand chemical degradation and multiple sterilizations.

 

The most common sterilization methods include:

 

  • Radiation (gamma/e-beam)
  • Chemical (ETO)
  • Autoclave (steam)

 

Chemicals to consider for contact with the device could be:

  • Intravenous medications
  • Blood/Fluids/human tissue
  • Hospital cleaners – bleach, isopropyl alcohol, peroxides

 

5. Polymer Characteristics

 

What mechanical properties does the polymer need to fulfill?

 

Selecting a plastic material is based on a number of traditional material requirements such as strength, stiffness or impact resistance. Engineered thermoplastics like PC, PEEK, PPSU, POM, show excellent mechanical properties at low and high temperatures. These properties are required for a variety of climate conditions, including during transportation, where the influence of temperature on drop impact may result in different outcomes for device integrity.

 

Your machinist should be able to give you details about all the plastics in their portfolio such as:

 

  • High wear resistance
  • Tensile strength
  • Temperature resistance
  • Corrosion resistance
  • Durability
  • Dimensional stability

 

6. Aesthetics

 

Does the end product need to be a certain color or have certain qualities?

 

For instance, if it is a prosthetic for a foot, the polymer needs to be machined a certain shade to match skin tone.

 

7. Other Material Selection Factors

 

Anything else?

 

Other factors to consider and discuss with your machinist include additives for increasing the performance of the polymer, manufacturing process as well as the cost. Take into account the following:

 

  • Radiopacity
  • Conductive
  • Lubrication
  • Manufacturing feasibility
  • What manufacturing processes are you using and why?
  • Technical performance
  • Can we make this product with the material, and can we make it well?
  • Economics
  • If we can make it, can we make it for a reasonable cost?

 

At AIP, we are unrivaled experts in medical grade plastic machining.
Talk to our team about how to bring your project from concept to completion.

 

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