Metrology and Inspection Techniques for Precision Machined Ceramic Components

AZoM talks to Scott D. Mittl, Vice President of Sales at Insaco, about the grinding operations and inspection processes used at their factory.

What type of machine does Insaco use for CNC Grinding Operations?

Insaco has a couple hundred machine tools in our 80,000 square foot factory.  Almost all have CNC controls to varying degrees.

Is CNC Grinding or machining suitable for small batch orders or is there a minimum batch size required?

As a job shop, Insaco will quote customer requirements for small lots or even single piece, as well as of course large lots or for ongoing series production.

For example, Insaco makes ceramic collars to position rods in Quadrupole Mass Spectrometers for several manufacturers requiring tolerances to one micron. We also make guide and form rollers for metals and fibers processing.  

What steps do you take to ensure high levels of accuracy throughout a machining cycle that may run for several hours?

Insaco works to a robust Quality System that meets ISO 9001-2008 requirements.  Part of the Process Plan established for every part we fabricate includes first piece QC signoffs for each operation as well as mid lot inspections for SPC control where appropriate.

Can you provide an insight into the type of abrasive wheels that you employ to machine different materials or to generate certain surface finishes?

Diamond grinding wheels are available in metal-bond, glass-bond and resin-bond forms.  Each has certain advantages and limitations for performance in our work.  We have many years of history to guide our decision on what to use to achieve desired cut rate and finish.

Do you always have to employ diamond abrasives?

Most work at Insaco is performed with fixed or free diamond abrasives.  Other super hard abrasives like CBN do have a role in limited applications.  Some polishing operations benefit from application of varying chemistries as well as abrasives.

Insaco does have experience working with pretty much all types of diamond grinding wheel compositions and grits.  Exactly how and when each type is chosen has become a trade secret we prefer not to discuss.

Are there any situations where you have to produce bespoke or customised tooling?

Insaco makes our own form tools to be diamond plated for specialty work.  We also make fixture and work holders in house for our use.

Do you provide certification in accordance with any particular standards?

Our QC System is designed to meet requirements of ISO 9001-2008 and AS9100 although we are not formally registered.  We meet or exceed MIL Specs and are ITAR registered. Our QC System is routinely audited successfully by some of the biggest names in the Defense, Semiconductor and Medical fields.

Can you provide an outline of the type of inspection facilities and techniques you employ?

All parts we fabricate are visually inspected with features measured per drawing on 100% basis for small lots and sampled per ANSI/ASQ  z1.4 2003 requirements on larger lots.  Dimensions are normally noted on a range report to later certify all shipped parts meet drawing requirements.  Full reporting on a tagged part by part basis is available when customers require this.

Do you use any forms of automated inspection?

We operate two CMM instruments we program for multiple “taps” of multiple features on complex parts.  Other inspection instruments like our three Talyronds are programmed to evaluate cylindricity for example, and our Zygo Mark IV Interferometer is likewise programmed for optics inspection work.

I would imagine temperature control within inspection areas is important, what’s your approach to this issue?

Insaco’s QC lab is temperature and humidity controlled.  This room is also segregated on it’s own concrete slab to minimize transfer of vibrations from the production shop area.

Are there any labelling techniques that can be used to establish serial numbers i.e. laser marking?

Insaco operates a laser scribe instrument for sequential numbering of ceramic and sapphire parts where customers will benefit.  The laser marking is legible to OCR requirements and remains permanently after full ultrasonic bath cleaning. We don’t currently use lasers for machining.

What does the future hold for Insaco?

Insaco management is always looking for new developments in machine tools and inspection instruments that might provide us with improved capability or capacity to meet our customer needs.  We are active every year with large capital expenditures to keep Insaco on the forefront in our industry.

We also have in-house development of systems that allow automation wherever it can make sense for some higher volume production needs.  This allows us to run some areas of our shop “lights out” on weekends for example in order to increase capacity and cut costs.  We also have developed work cells for efficient production of smaller runs of very unusual parts.

About Scott D. Mittl

Scott D. Mittl, has been an employee of Insaco® since 1990 and is responsible for sales engineering activity including quotations and account management. He takes an aggressive proactive approach to developing new customers and new product applications.

This approach includes developing subcontractors to further enhance Insaco®'s machining capability in any non-metallic material. He has the technical expertise and experience in materials to aid customers in successfully designing products out of materials commonly machined by Insaco®.

He has a B.A. in Applied Sciences and a B.S. in Metallurgy and Materials Engineering from Lehigh University and is a member of the American Ceramic Society.