Lot Acceptance Testing (LAT)

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product.thumbnail.alt Lot Acceptance Testing (LAT) - Ohmcraft Resistors > Surface Mount Resistors

Lot Acceptance Testing provides screening and qualification tests to enable the use of Exxelia Ohmcraft’s standard parts in flight applications (Aerospace/Space). 

Exxelia Ohmcraft can screen and qualify its resistor products to MIL-PRF-55342, MIL-PRF-49462, NASA EEE-INST-002 (Level 1 or Level 2) or a custom test plan. LAT Testing includes but is not limited to:

  • Thermal Shock
  • Power Conditioning
  • High Temperature Exposure
  • Solderability
  • TCR
  • Load Life
  • Short Term Overload
  • Terminal Strength
  • Resistance to Solvents


Electrical Specifications

Value RR ΩResistance Value in kΩs, MΩs, GΩs, or TΩs
Tolerance± X% at VResistance Tolerance measured at specified voltage
TCR< [Ordering Coder TCR] ppm/ºC (Hot to TmaxºC, Cold to TminºC)
< 2*[Ordering Coder TCR] ppm/ºC (Hot to 125ºC, Cold to -55ºC)
TCR referenced to 25ºC
Working VoltageVVoltage across the resistor during application operation
Max Voltage RatingVMaximum Voltage based on resistance value or case rating
Max Power RatingWMaximum Wattage based on resistance value or case rating

 

Conformance Testing

Pre-Cap Visual Inspection

Prior to Conformance Test13 pcs

Conformance Test – 100% Screening

Visual Inspection

  • Magnification: 30x to 60x
100%
Mechanical Inspection3 pcs. (minimum)

DC Resistance

  • Per MIL-STD-202, Method 303
  • Measured at specified test voltage for resistance tolerance
100%

Thermal Shock

  • Per-MIL-STD-202. Method 107, Test Condition B (modified)
  • 5 cycles (MIL-PRF-55342), 10 cycles ( NASA level 2) or 25 cycles (NASA level 1)
  • Min. temp -55ºC, Max temp 125ºC
100%

High Temperature Exposure (SMT)

  • 100 hours at 125ºC
100%

Power Conditioning (Leaded)

  • 100 hours at Working Voltage at 25ºC
100%

Final DC Resistance

  • Per MIL-STD-202, Method 303
  • Measured at specified test voltage for resistance tolerance
100%

Conformance PDA: 5% (NASA Level 1 or MIL-PRF-55342), 10% (MIL-PRF-49462) or 15% (NASA Level 2)


Qualification Testing

GroupNASA Sample Size (Level 1 / Level 2)

Group 1

  • Conformance Testing: Basic Screening
100%

Group 2

  • Solderability
    • MIL-STD-202, Method 208
  • Resistance to Solvents (Leaded)
    • MIL-STD-202, Method 215
3 pcs / 3 pcs

Group 3

  • Temperature Coefficient (TCR)
    • Per MIL-STD-202, Method 304
    • Reference Temperature: 25ºC
  • Low Temperature Storage
    • -65ºC no load dwell for 24±4 hours
    • +25ºC ambient no load dwell for 2-8 hours
  • Low Temperature Operation
    • -65ºC no load dwell for 1 hour
    • Working Voltage for 54 minutes
    • +25ºC no load dwell for 24±4 hours
  • Short Time Overload
    • 2X Working Voltage for 5 seconds
10 pcs / 6 pcs

Group 4

  • Resistance to soldering heat
    • MIL-STD-202, Method 210, Test Condition B (modified)
    • 260ºC for 20 seconds
  • Terminal Strength (Leaded)
  • MIL-STD-202, Method 211 Test Condition C
  • 16 ounces ± 1 ounce for 10 seconds
9 pcs / 6 pcs

Group 5

  • Shock (Leaded)
    • MIL-STD-202, Method 213B, Test Condition I
  • Vibration (Leaded)
    • Per MIL-STD-202, Method 204, Test Condition D
9 pcs / 6 pcs

Group 6

  • Load Life
    • Per MIL-STD-202, Method 108
    • Working Voltage for 1000 or 2000 hours at 25ºC
12 pcs / 9 pcs

Group 7

  • Resistance to Bonding Exposure (SMT)
    • Solder mounted to a ceramic test plate
    • 4-12 hours stabilization at 25ºC
10 pcs / 5 pcs

Group 8

  • No Applicable Tests
 

Group 9

  • High Temperature Exposure
    • 125ºC for 100 hours
5 pcs

 

Custom Configurations Available Upon Request

Please consult with our knowledgeable sales staff for help specifying custom parts to meet your needs.

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Frequently Asked Questions

Find answers to the most frequently asked questions about our products and services.
Ohmcraft / Micropen : Do they have an end-to-end process?

A full-service partner who can collaborate on product design, rapid prototyping, manufacturing, testing, and supply chain services is ideal. Consolidating all activities under one roof can reduce costs and time to market. It also allows for problems to be addressed quickly and eliminates the finger-pointing when multiple suppliers are involved. You should choose a partner who will complement your own team, adding value end-to-end.

At Micropen we have expertise from design through manufacturing and responsive support throughout the product lifecycle. Our flexible printing manufacturing services can meet the needs of any company, from a start-up to a major OEM.

Ohmcraft / Micropen : Can they scale and respond to changes in demand?

It is important to choose a partner who can meet your production requirements now and into the future. The manufacturer should be agile and flexible in regard to your demand changes and able to meet your deliveries as agreed. This requires that they have a well-understood supply chain of raw materials and lead times. Make sure to ask about this when selecting a partner. At Exxelia Micropen we have the resources and experience to respond to growth and demand increases.


This is especially important in today’s roller-coaster supply chain economy. We have excellent partnerships with suppliers of ink, substrates, and other raw materials and have a well-established process for supply chain management and production scheduling.

Ohmcraft / Micropen : Could you envision them as a long-term partner and collaborator?

The most successful partnerships are long-term and collaborative. The resources on each team should have a shared understanding of the objectives and requirements,
and the chosen supplier should be seen as an extension of your team. This allows challenges to be solved quickly and assures that the project will be completed on
time and within budget. Regular meetings, passing files back and forth, and engaging experts in different functions of the organization are all elements of a partnership and lead to the success of the project. Your partner should be proactively communicating throughout the product lifecycle. Your partner may also consider investing in the partnership for the long-term. Over time, as you work together, you’ll be able to apply learnings and efficiency to not only one product but a portfolio of products in a cost-effective and optimized way.

At Exxelia Micropen, we are committed to working collaboratively, starting early in the product design stage. We will share with you our accomplishments, manufacturing controls, and quality assurance process steps. We want you to get to know us, and the earlier we can engage with you as an integrated partner to your design team, the better. Most of our customers have been with us for years and we value a platform approach where we can apply our learnings to product extensions and next-generation designs.

Ohmcraft / Micropen : Do they have relevant experience in medical device design, prototyping, and production?

There are complex requirements in the healthcare industry, and a proven track record in the understanding of proper documentation, revision control, and maintenance of device history records and safety regulations will go a long way to ensure that your project is successful. An experienced partner can provide advice on design, suitableinks, techniques, and steps to optimize the process.

This can lead to valuable time and cost savings over the course of the project. There is no substitute for experience in partnering on the design and manufacturing of printed electronics for the implantable medical device market. Exxelia Micropen has over 25 years of experience in working with top-tier medical device companies, printing electronics on endotracheal tubes, ablation devices, balloon catheters, etc.

Our engineering and development teams have the necessary technical expertise, and our production, test, and quality teams understand what it takes to manufacture volume devices while maintaining competitive pricing. We understand that we are adding value to devices that will be used to save or enhance a patient’s life.

Who is Exxelia Ohmcraft ?

Established in 1982, Exxelia Ohmcraft quickly became the leader in thick film, high voltage, high precision resistor design and manufacturing. Expertise in high voltage resistors and high value resistors has enabled our design engineers to meet and exceed the most challenging product specifications. Our technology allows engineers to design application-specific resistors to fit the needs of our collaborative partners. xelia Micropen technology has the same superior technical performance in all of our surface mount resistors, leaded resistors, dividers and networks. Our ability to print on three dimensional substrates allows us to truly customize each project we commit to. Exxelia Ohmcraft resistors provide industry-leading performance in high voltage, precision, TCR and TCR tracking, VCR and VCR tracking, low noise, stability and pulse-withstanding capability.

Today, the Exxelia Micropen electronic printing system is the core technology for the design and manufacture of Exxelia Ohmcraft’s complete line of resistors – chip resistors, flat leaded resistors, axial leaded resistors and custom resistive product solutions. In addition, Exxelia Micropen, the sister division, utilizes the Micropen electronic printing system to design, develop and manufacture some of the world’s most innovative electronic devices.

Contact us today for a personal, confidential discussion about your own innovative application to see how we can make it come to life faster, easier and better.

Are your products compliant with defense standards?

Yes. Exxelia meets defense industry requirements through its EN 9100 certification and compliance with military standards (MIL-STD, STANAG). Our components are qualified for critical applications such as RF systems, embedded electronics, guided munitions, or radar systems. Some products are also subject to customer-specific qualification procedures.

What benefits do your certifications bring to the railway sector?

The railway industry demands durability, reliability, and long service life. While a dedicated certification like EN 9100 is not required, Exxelia applies IRIS standards and complies with IEC/EN regulations specific to railway applications. Our quality processes ensure component compliance for trains, metros, and tramways, including fire safety and electromagnetic compatibility.

Are your components certified for use in medical devices?

Yes, some of our facilities are ISO 13485 certified, the quality standard for medical devices. This certification enables Exxelia to design and manufacture components (such as coils, sensors, or capacitors) used in high-reliability medical equipment, including MRI scanners, ventilators, and imaging systems.

Why is EN 9100 certification important for the aerospace and space sectors?

The EN 9100 standard ensures a rigorous quality management system tailored to the critical requirements of the aerospace, space, and defense industries. It is required by major OEMs such as Airbus, Safran, Thales, or CNES. This certification guarantees product traceability, risk management, and compliance with international standards.

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