ARTICLE: What Makes a Good Machine Shop?

You may be looking around for a machine shop to contract out your project to. Your business directory is filled with machine shops even in your local area and countless others in your state or across the country, even overseas. So, how can you narrow down all these choices to get the best product for the best value? Whether you need micro-precision CNC machining of a single prototype with tolerances down to 1/10,000 or a run of 100,000, here are some features to keep in mind and questions to ask during your search process.

Elements of a Good Machine Shop

  • Certification
  • Facility
  • Expertise
  • Inspection Capabilities
  • FAI
  • Professionalism
  • On-Time Delivery Record

Certification

ISO is the International Organization for Standardization. Headquartered in Bern, Switzerland, ISO is the world's largest developer of standards used in industry and business. It is called ISO from the Greek isos, which means "equal."

A standard is a definite level or degree of quality that is proper and adequate for a specific purpose.

A machine shop posting a certificate stating that they are in compliance with ISO 9001 from a recognized accreditation body means that the business follows high standards of quality management systems. This certification is not easily gained and Prominex is audited regularly by TÜV SÜD America to ensure its continued compliance.

Beware of any shop not prominently displaying a ISO 9001 certificate. Ask to see it and if they can't produce one ask why.

The Facility

Does there appear to be ample space or are parts stacked one on top of the other? Is the place clean or messy? Maybe your job doesn't require a NASA style clean room type environment in which case there's no sense paying for it. On the other hand, a shop that is messy looking may produce messy looking parts that won't do the job for you.

Equipment

Is the equipment new, top of the line and well-maintained? Ask when the last time the machines were calibrated. As a piece of equipment gets older it's ability to hold narrow tolerances slips, particularly if it has not been regularly maintained and periodically calibrated. Prominex' inspection equipment is inspected and calibrated yearly by third party agencies.

Expertise

Is the company capable of handling your entire project in-house or do phases of the process need to go to outside vendors? If so, are these subcontractors also ISO 9001 certified? It is fairly common for final steps such as plating or painting to be outsourced but if steps of the machining phase need to go outside the shop, this could present problems. Ask what, if any, steps of your project will need to sent to an outside firm. What is their relationship with the outside vendor? Is it a long term, trusted connection?

Inspection capabilities

Quality of the product coming out of the shop should be foremost in the minds of everyone working for the company. What is the state of the quality control section of the business. Do they use coordinate measuring machines (CMM) to determine that the products are precisely what you ordered? CMM is today's cutting edge in metrology and a shop that utilizes these to assure quality is likely one that can produce what you want to the standards you need. Ask about quality control what inspection equipment they employ. Ask for their parts acceptance rate from other customers. It it is in the 99.5% range or higher you know you are dealing with a shop that knows its business.

FAI

Another sign that a shop may be a good partner is whether they employ FAI, first article inspection. This is a parallel procedure to the manufacturing process and results in complete transparency of each phase, from drawings to shipping. Often times the customer requires that the first product coming off the line be sent to them for inspection before the entire run is done. Accompanying the first shipment is documentation of every step of the production process including the drawings, raw materials, G codes for programming the machines, etc. FAI is another sign that a shop is quality oriented as such inspections can save much time, money and logistics at the customer's end.

Professionalism

Finally, do the people you deal with come across as knowledgeable professionals? Do they furnish references to former customers or have testimonials they can show you? Do they belong to professional and trade organizations that keep them up to date on latest developments in their field?

And what about their on-time delivery record?

Can they demonstrate a track record of delivering a job when they say it will be delivered. Getting answers to these questions will help you predict the kind of experience you can expect if you choose them to do your job.