Category Archive: Quality Management
A 19-inch rack is a standardized frame or enclosure for mounting electronic equipment modules. Common uses for these racks / enclosures include datacom, telecommunication, audiovisual production equipment, scientific equipment, and networking hardware. The weird thing: almost nothing on a 19″ rack measures 19 inches. The term comes from the width of the front panel of the boxes that are installed in the rack. Other common rack hole-to-hole spacing includes 23″ (566.7 mm) and 24″ racks (592.1 mm).
EIA stands for the Electronic Industries Alliance. It was a group of trade associations for electronic manufacturers in the United States. The current iteration or standard is EIA-310-D. Note: these standards are not enforced by any governing bodies, therefore compliance isn’t enforced.
The document outlines specific guidelines for several components:
- Rack Units (U) – hole spacing for standard racks on the mounting flange is spaced in groups of three holes. This three-hole group is defined as a Rack Unit (U). 1U is 1.75″ (44.45 mm) of vertical space
- vertical hole spacing – repeating pattern of holes within one Rack Unit of 1.75″ (44.45 mm). Whole spacing alternates at 1/2″ – 5/8″ – 5/8″ and then repeats. “U” space starts and stops in the middle of the 1/2″ holes
- horizontal hole spacing – specified at 18 5/16″ (465.1 mm), but this dimension is not universal so most manufacturers will use equipment mounting slots to allow for variations
- rack opening – specified at a minimum of 17 3/4″ (450 mm)
- front panel width – 19″ (482.6 mm), but the physical width of the rack itself can vary significantly
A&J’s standard equipment specifications for our three standard racks can be found on our website.
What the EIA-310 Standard Doesn’t Include
Despite having a document defining standardized 19″ racks, there are still several details left out.
- Are the rack-mounting holes threaded, square or round?
- How many posts does the rack have? (2, 4 or even 6) Are there any obstructions between these posts?
- How deep is the racks mounting depth?
- What is the thread type?
- How much space is between the front or rear door and the front or rear post?
A Brief History
The term relay rack first appears in the world of telephony, but was also being used in railroad signaling by 1911. However, there is little evidence that these early racks had any standardization.
A 19″ rack format with 1.75″ or 1U was established as a standard by AT&T around 1922 in order to reduce the space required for repeater and termination equipment in a telephone company’s central office. Their engineering department created a family of modular panels “designed to mount on vertical supports spaced 19.5 inches between centers. The height of the different panels will vary, but in all cases to be a whole multiple of 1.75 inches.”
By 1934, it was an established standard with holes tapped for 12-24 screws with alternating spacings of 1.25″ and 0.5″. The standard was again revised in 1992 to comply with the 1988 public law 100-418, setting the standard U as 1.75″ (44.45 mm). The 19-inch format has more or less remained constant since despite the fact that the technology mounted within has changed considerably.
Choosing a manufacturer to build your COTS or custom electronic equipment enclosure is a big decision. With money and so many important factors at play, it requires careful consideration. Before committing, there are several questions you should ask to get a better idea of what they do and the level of quality they offer in both service and product.
What is your experience with similar projects?
Look for a history of satisfied customers in your industry. Each industry has different regulations, requirements and considerations, so your electronic enclosure manufacturer should understand your unique conditions — and how to design an enclosure that will protect your sensitive electronic equipment components.
Will my enclosure be manufactured in-house?
When the majority of the manufacturing process is completed in-house, design and production teams can work in tandem to ensure that specifications and deadlines are met. Other benefits include: quality control, reduced manufacturing time and controlled costs. Plus, having direct access to both teams becomes an advantage if they need to accommodate any changes or modifications.
How do you accommodate special requests?
One of the primary factors driving your selection process should be choosing a manufacturer that can resolve your challenges and provide a solution. At A&J Manufacturing, we can custom design and fabricate enclosures within our state-of the-art facility in California. Our team works closely with each customer to produce the exact enclosure your application requires with our knowledgeable and experienced design engineers.
Make sure you’ve done your homework to properly identify the type of environment in which the enclosure will be used and any requirements that affect the materials, equipment or components involved:
- Need for UV resistance
- Plant or factory conditions
- Temperature extremes
- Presence of any electromagnetic interference
- Required size and available space
- Ease of accessibility
- Mounting requirements
- Thermal management for components
You should also be aware of their process controls and how they handle design deviations or problems. Remember to examine how they manage their communication and inspection / progress reports.
What certifications do you carry?
Quality is essential! Does your manufacturer have the appropriate certifications required? Each industry has different certification requirements such as AS9100D or RoHS compliance. It’s prudent to discuss ALL requirements in advance.
Some applications will have particular performance standards that the enclosure must meet too, such as NEMA and UL. These standards are met during testing when an inspector determines if any dust, moisture or other damaging elements have entered the enclosure.
You should know if they keep their certifications up to date and have training programs to keep staff certified in their skills.
What are your facilities and equipment like, and what kind of company culture do you promote?
Manufacturing is a versatile field that keeps on advancing with technological changes. Ensure that your ideal partner is well informed and knowns how to use modern manufacturing technology and equipment. It would be hard to build your product if the equipment used is outdated. If you’re interested in A&J’s production equipment and would like to “visit” our facilities, check out our Factory Tour video on YouTube.
Lastly, find out what kind of company culture they promote. Do they have the same business values you do? At A&J, its about strong communication, allowing flexibility in our employee’s day-to-day schedule, creating accountability and making sure that our people feel like they matter.
While the First Article of Inspection isn’t the only type of test to perform, it is certainly a vital one during the production of electronic equipment racks. The goal is to ensure that the produced good(s) meet a client’s specifications.
What is a First Article Inspection?
A first article inspection occurs when an authorized person takes one or several parts from the first production run. Those parts are then compared to the client specifications to verify that they match exactly. First Article Inspection (FAI) is required under AS9102 or if a custom requires one before the manufacturing process begins.
At A&J we select a random sample and inspect every dimension and specification of this sample against the drawing.
Pass vs. Fail
Again, this inspection is to ensure that everything meets expectations before your electronic rack production run can continue. And operations pause until a part or the rack in its entirety passes the FAI.
If a component fails, production halts until an engineer or the production floor machinists can find the cause and address it. Afterward, another FAI occurs to assess whether production can resume. These quality checks are exceptionally important in industries with critical applications such as defense, aerospace and medical devices.
A&J follows the guidelines of the Aerospace First Article Inspection Requirement (AS9102B), a standard associated with SAE International. The purpose is to provide objective evidence that all engineering design and specification requirements are properly understood, accounted for, verified and documented. It also serves as a documented quality record for both the supplier and customer to use as a form of accountability.
When Should You Request a FAI?
In addition to the first production run, several other scenarios exist that make a FAI appropriate:
- A production lapse of two+ years
- Alterations in the materials, sourcing, tools or manufacturing location
- A delta or partial FAI can be requested when a specific part of component goes through design changes
Alternatively, it might be unnecessary to perform a FAI if the production batch is small or if the manufacturer is well accustomed to making the part or product you’re requesting.
What Happens During a FAI?
At A&J, our Quality Assurance Manager uses a checklist to maintain thoroughness. And in 2019 we invested in a coordinate measuring machine (CMM) to compare the produced part with their specifications. As always, the goal is to see if they differ and check any variations within a customer’s tolerances.
To validate a product has been correctly manufactured, a First Article Inspection Report is drafted. It usually consists of three forms:
- part number accountability – used to summarize the part being inspected and any associated sub-assemblies or details
- product accountability – used for all raw materials, specifications, processes and functional tests as defined in the design requirements
- characteristic accountability – summarizes dimensions, tolerances, as well as actual measurement results for every part of the original drawing and is often accompanied by a ballooned drawing or bubble drawing
After the engineering package is “released”, all hardware, parts and materials (per the PO) will be included in the FAI package, and as necessary, include an inspection for each item. The executed report is submitted to our customer for approval before production resumes and/or no less than 5 working days prior to expected shipment date. A customer is required to provide rejection reasons before corrections are performed.
A Crucial Component of our Quality Management System
The benefits of a FAI report:
- Ensure the production process is reliable, repeatable and consistent
- Ensure that there is a clear understanding of requirements and unique specifications between the customer and the manufacturer. It also helps verify the accuracy of drawings and component dimensions
- Develop a clear communication process (and potentially future collaboration)
The FAI process helps find potential errors in dimensions, clarify finish requirements and eliminate any design questions around tolerances.
For more information about A&J’s FAI capabilities, please contact us today.
The need to store vital electronic equipment and data requires purchasing electronic enclosures or racks. Understanding how long it may take for you to develop the rack’s interior layout, purchase the racks, and having them installed will allow you to develop a realistic timeline that will guide you in your planning process.
With any project, knowing the steps that should be accomplished to earn a successful outcome is important. From there, you can work backward to establish a realistic completion date. Timelines for each and every project will vary, but tend to follow a general pattern. Below is an outline of expected steps so that you can plan for your electronic enclosure purchase.
Estimated Time & Steps Required to Manufacture an Electronic Enclosure
1 day – 1 week: Take inventory of all electronic equipment that will need to be mounted in the rack and set up an appointment to meet with your rack manufacturing professional to evaluate your requirements.
2 to 6 weeks: To allow our engineers to develop a proposal and a rack layout. Plan to meet with them regularly or at least once more to review the proposal and the layout to ensure it meets your objectives. Allow for additional time to make changes to fine tune the proposal or design specifications.
2 to 4 weeks: You know the speed at which your organization makes purchasing decisions. A purchase approval can take anywhere from a few days to several months. And unfortunately is a wild card you cannot control. So its best to plan for more than enough time to to ensure you have approval from all decision makers or stakeholders.
1 week: For purchasing to process and send the order; and for us to receive and process the order.
2 to 3 days: Final drawings are approved and released to production.
4 to 14 weeks: Depending on the backlog at any point in time, production time to complete your rack(s) can vary widely. Currently, lead times are generally 12 to 16 weeks for custom enclosures. Note: Standard lead times vary based on quantities, whereas, lead times for modified or custom orders will vary based on the complexity of your design/drawings.
3 days to 1 week: Typical shipping time required.
2 days to 2 weeks: Installation of your rack(s) is based on the amount of racks to be installed and the number of installers on the crew.
For planning purposes, you should expect it to take at least 4 to 6 weeks from the time you start planning your rack purchase of MCOTS electronic enclosures to the time it’s installed. If you need a modified or custom order, expect the timeline to be longer; between 12 and 16 weeks.
You don’t need to begin the planning and selection process on your own. Our experienced engineers at A&J Manufacturing can walk you through our catalog of options and design an option that works best for your unique needs. Contact us today to get started on your next electronic enclosure project.