AlphaTest Corporation microHELIX Test-Probes your fine-pitch connection

FAQs About Our MicroHELIX Pogo Pin Probes and Test Fixtures

Here are our answers to some frequently asked questions about 's MicroHELIX pogo pin probes and test fixtures that offer unparalleled performance, accuracy, and reliability. Our durable MicroHELIX probes have proven to last hundreds of thousands of test cycles, providing long-lasting, accurate, and reliable testing capabilities. Read on to learn more about made-in-the-USA products by .

  1. Are these pogo pin probes suitable for burn-in applications?
  2. How long do these spring contact test probes last?
  3. How much current can these semiconductor test probes handle?
  4. Where are our high-quality precision test probes and fixtures/sockets made?
  5. What fine pitch or center-to-center spacing can be achieved with our durable probes and precision fixtures?
  6. What diameters and lengths are available for the microprobes?
  7. What is the force of the pogo pins?
    • At , we offer standard catalog probes with various probe force options. If you require different force values, we can provide them upon request, including lower force with reduced travel. Here are the force options for our different series of probes:
      • S500 Series Probes: 0.5mm (0.020 inches) diameter; 30 grams (1.1 oz) and 90 grams (3.5 oz).
      • S400 Series Probes: 0.4mm (0.016 inches) diameter; 30 grams (1.1 oz) and 80 grams (3.5 oz).
      • S300 Series Probes: 0.3mm (0.012 inches) diameter; 30 grams (1.1 oz) and 60 grams (2.1 oz).
      • S200 Series Probes: 0.2mm (0.008 inches) diameter; 30 grams (1.1 oz) and 40 grams (2.1 oz).
    • MicroHELIX Semiconductor Test Probe Force:
      • For our MicroHELIX semiconductor test probe, we rate the force at the typical test compression, which is usually half of the maximum compliance. For example, a descriptive model name like "*3800/900/30@450/S1300s/S0a" indicates a force of 30 grams at 450 microns of compression.
    • Linear Relationship Between Probe Force and Travel:
      • To visualize the relationship between probe force and probe travel (stroke, compression, compliance), we have provided a force chart for the *3800/900/30@450// Probe Group. The probe force is shown on the vertical axis, while travel is represented on the horizontal axis.

      • Force Chart 30@450

  8. What are the features of your miniature probes?

  9. Categories (Cat): (1) standard, (2) custom, (3) special
    Construction (Const)
    Device Under Test (DUT) contact description: Plunger, tube end
    input/output (i/o) end description: i/o Pin, wire, tube end
    Pin Tip Shapes: sharp (s), radiused (r), flat (f), 4-point crown (c4)
    μHELIX tube&spring assembly (probe body)
    Diameter (ø)
    Cat Const DUT contact> i/o contact + Features Description Drawing
    1 2-piece plunger annular Basic μHELIX probe body;
    plunger (s,r,f,c4)
    Basis uHELIX Probe
    1 3-piece plunger i/o pin secondary pin probe body;
    plunger (s,r,f,c4);
    i/o Pin (s,r,f,c4)
    i/o pin version
    2 3-piece plunger i/o wire i/o wire probe body;
    plunger (s,r,f,c4);
    wire installed at i/o end
    capture feature
    1 2-piece plunger i/o pin capture feature probe body;
    reduced ø at i/o end;
    plunger (s,r,f,c4)
    capture feature
    2 1-piece annular annular transposer probe body S0a/S0a
    3 1-piece annular annular capturable transposer probe body;
    reduced ø at one end
    capture feature
    2 1-piece annular annular capturable transposer probe body;
    reduced ø at both ends
    2 2-piece annular annular low resistance, captured transposer probe body;
    reduced ø at both ends;
    internal Cu wire for high conductivity
    2 2-piece plunger crown short, i/o crown probe body;
    crown at i/o end;
    plunger (s,r,f,c4)
    2 2-piece plunger crown short, captured i/o crown probe body;
    crown at i/o end;
    reduced ø at i/o end;
    Plunger (s,r,f,c4)
    capture feature
    3 Custom Custom Custom Custom Custom  

  10. What kind of plating is used on the semiconductor probes?
    • We use a gold strike/Type III/Type II Gold plate with a thickness of 60-80 micro inches on all tube/coil assemblies, plungers, and pins in our standard catalog probes. Nickel (to repel solder buildup) and PdCo (Palladium Cobalt to repel solder buildup) may be applied for special orders.
  11. What equipment do I need to drill guide holes for the small microprobes?
    • For drilling guide holes, you'll need an xy position accuracy of 2.5 microns (0.0001"), the ability to peck the drill, and a spindle speed of at least 7,000 rpm (preferably programmable from under 7,000 to 50,000 and ideally programmable from below 7,000 to 120,000 rpm).
    • The CNC drill instructions may vary slightly based on the available spindle speed. To prevent heat buildup, drill with a pecking action. This will clear debris from the hole and minimize loading in the drill flutes. Maintain a high cutting speed. For comparison, use a 10,000 rpm spindle speed when determining the cutting speed for these drills.

    • Example: Drill cutting-speed vs Drill Size using 10,000 rpm
      cutting-speed in units/time = PI*(Dia in units)*(rpm)/(60 sec/min)
      Drill Size Cutting Speed Application
        microns inches mm/sec inches/sec guide-hole for:
      #74 572 (0.0225) 300 (11.8) S500 probe body
      1/64" 397 (0.0156) 208 (8.2) S500 plunger | i/o pin
      #77 457 (0.018) 239 (9.4) S400 probe body
      #80 343 (0.0135) 180 (7.1) S400 plunger | i/o pin
      S300 probe body
      #88 240 (0.0955) 126 (5.0) S300 plunger | i/o pin
      S200 probe body
      #96 160 (0.0063) 84 (3.3) S200 plunger | i/o pin

    • When it comes to the guide-plate material, its mechanical characteristics (see Tech Note TN0019) will influence the CNC drill profile. This is important to ensure proper debris removal and flute cooling.
    • Generally, your CNC machining operation should be able to determine the best spindle speed, feed rate, and peck pattern for drilling straight holes in different materials. However, if you encounter any issues, feel free to reach out to for suggestions. We're here to help.
  12. What is the history of the MicroHELIX Series Test Probes?
    • The MicroHELIX Series Test Probes were developed by as spring contacts for custom test probes and fixtures. These probes' unique construction allows for tighter pitch and closer centers in test sockets and fixtures. They were initially used in test fixtures and are now available in the electronic test and measurement industry. These microprobes have gained a reputation for quality and durability over the past 30 years.
  13. How long does delivery take?
    • Our catalog probes are either in inventory or can be delivered within 2 weeks. Custom probes that are not included in our catalog can generally be shipped within 3 to 4 weeks. Special probes, designed from scratch, may require 2 to 12 weeks. We can also build non-standard combinations from stock components, so please inquire if you cannot find the combination you need and can wait a few weeks.
  14. What other made-in-the-USA products does offer?
    • In addition to customizable probes with various lengths and tip configurations, we also specialize in building "difficult" fixtures and sockets for fine-pitch, small features, challenging topographies, and high-frequency applications. We stay up-to-date with market trends in testing and test probe requirements through our experience developing these made-in-the-USA products. also offers the hand-held μKELVIN™ fine-pitch Kelvin Test Probe, which measures low resistance values on various surfaces.
  15. Do products comply with RoHS and REACH directives?
    • Our manufacturing process involves machining and/or plating materials purchased from qualified suppliers. ensures that no hazardous substances listed in the RoHS and REACH directives are added or exposed to metals, plastics, or resins used in our products during assembly.
    • We comply with Directive 2011/65/EU and Directive 2015/863/EU, which restrict the use of certain hazardous substances in electrical and electronic equipment.

    • Lead (Pb)Polybrominated Diphenyl Ethers (PBDE)
      Mercury (Hg)Bis(2-ethylhexyl)phthalate (DEHP)
      Cadmium (Cd)Benzyl Butyl Phthalate (BBP)
      Hexavalent Chromium (Cr VI)Dibutyl Phthalate (DBP)
      Polybrominated Biphenyls (PBB)Diisobutyl Phthalate (DIBP)

    • At , our products adhere to the EU RoHS Directives and do not contain excessive levels of restricted substances, as verified by our vendors. Please note that we do not independently verify vendor-provided certification, but we trust the accuracy of their information. Some of our custom test probes, fixtures, or sockets may contain RoHS-compliant solder.
    • Regarding the REACH Directives, we assure you that our products do not contain any substances listed as Substances of Very High Concern (SVHC) in concentrations exceeding the Maximum Concentration Value (MCV).
  16. What is the NCAIS code for 's products?
    • All our products, including probes and fixtures or sockets, fall under the NCAIS code 334515 - Instrument Manufacturing for Measuring and Testing Electricity and Electrical Signals.
  17. How can I request a price quotation, place an order, or receive additional technical support?
    • You have multiple options:
      • Visit our Register page and leave a message.
      • Send us an email at or
      • Call us at 360 462-0201 during regular business hours: Monday-Thursday, 8 a.m.-5 p.m. and Friday, 8 a.m. to noon.