{"id":579,"date":"2026-10-21T11:54:05","date_gmt":"2026-10-21T03:54:05","guid":{"rendered":"http:\/\/www.anamstone.com\/blog\/?p=579"},"modified":"2026-10-21T11:54:05","modified_gmt":"2026-10-21T03:54:05","slug":"what-is-the-calibration-method-for-thermal-analysis-instruments-4894-d09616","status":"publish","type":"post","link":"http:\/\/www.anamstone.com\/blog\/2026\/10\/21\/what-is-the-calibration-method-for-thermal-analysis-instruments-4894-d09616\/","title":{"rendered":"What is the calibration method for thermal analysis instruments?"},"content":{"rendered":"

When I first started working as a thermal analysis instruments supplier over a decade ago, I quickly learned that many new lab managers and technicians skip the calibration step\u2014until they get a result that\u2019s way off and have to re-run their entire experiment. That\u2019s not only a waste of time but also a hit to their bottom line. Today, I want to walk you through what calibration for thermal analysis instruments actually means, why it\u2019s non-negotiable, and the methods we rely on here at our team to keep instruments accurate. Thermal Analysis Instruments<\/a><\/p>\n

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First, let\u2019s ground this in what thermal analysis even is. These instruments measure changes in a sample\u2019s properties as temperature, time, or atmosphere shifts. Examples include Differential Scanning Calorimetry (DSC), Thermogravimetric Analysis (TGA), and Dynamic Mechanical Analysis (DMA). Every part of these tools\u2014from the heating elements to the temperature sensors to the sample pans\u2014drifts over time, from regular use, temperature cycles, even environmental factors like humidity. Calibration is the process of verifying that the instrument is reading and reacting as it should, against a known reference, to ensure results are trustworthy.<\/p>\n

Let\u2019s break down the core types of calibration methods, tailored to the most common thermal instruments our customers use. I\u2019ll focus on the ones we perform in-house at our service lab, which we also walk customers through when they take our training sessions.<\/p>\n

Starting with temperature calibration. This is usually the first step anyone should do, because if your instrument\u2019s \u201c100\u00b0C\u201d is actually 98.5\u00b0C, your melting point or glass transition temperature results are useless. For DSC and TGA, we use standard reference materials (SRMs) from national metrology bodies\u2014things like indium, tin, lead, or zinc. These materials have well-documented, pure melting points that are agreed upon globally. The method is straightforward: you run the SRM through the same heating cycle you\u2019d use for your samples, then compare the instrument\u2019s measured melting point to the true, accepted value. If there\u2019s a deviation, you adjust the instrument\u2019s temperature offset. For example, indium melts at 156.60\u00b0C. If your instrument reads 155.8\u00b0C when you run indium, you add a 0.8\u00b0C offset to all subsequent temperature readings. We also do this for cooling cycles, because some drift is different when heating vs. cooling, especially for DSC where phase changes can be affected by cooling rate.<\/p>\n

For TGA specifically, mass calibration is just as critical. TGA measures how much a sample\u2019s weight changes as it heats up\u2014like when a polymer decomposes or a material loses moisture. If your mass reading is off, you might incorrectly calculate the amount of filler in a plastic or the residue left after combustion. The standard here is a precision mass calibration standard, usually a set of weights traceable to international standards. We place a certified mass on the TGA\u2019s sample pan, let the instrument measure it, and compare that to the known mass. If there\u2019s a 0.1% error, we adjust the balance calibration. We also do a \u201cblank run\u201d empty test to account for any weight change from the pan itself, which can come from oxidation or small amounts of residual sample left from prior runs. A common mistake here is skipping the blank run and assuming the pan doesn\u2019t change\u2014we\u2019ve seen customers think a sample lost 5% moisture, when really the pan itself lost 0.5% during the run, so the actual moisture was 4.5%. That\u2019s the kind of error that leads to rejected batches or failed regulatory tests.<\/p>\n

Next, heat flow calibration, which is most important for DSC. DSC measures the difference in heat flow between a sample and a reference as they heat or cool. If this is uncalibrated, you can\u2019t get accurate enthalpy values\u2014like how much heat is released during a curing reaction in epoxy, or the heat of fusion of a metal. The SRMs here are materials with known enthalpies of fusion, again indium is common, or tin. The method works similarly to temperature calibration: run the SRM, compare the measured enthalpy from the DSC to the certified value, and adjust the heat flow gain. For example, indium has a heat of fusion of 28.45 J\/g. If your DSC measures 28.1 J\/g, you boost the gain slightly to get it to match. We also do a baseline calibration, which is a blank run with no sample or reference. This accounts for any heat flow from the instrument itself, like heating the furnace or sensor noise. Without a proper baseline, small endothermic or exothermic events (like a minor crystallization) can get lost in the noise.<\/p>\n

For Dynamic Mechanical Analysis (DMA), calibration is a bit different because it measures mechanical properties\u2014storage modulus, loss modulus, damping\u2014rather than just temperature, mass, or heat flow. DMA has more variables: force, displacement, frequency, and temperature. The key calibration here is force calibration. We use standard weights to apply a known force to the DMA\u2019s probe, then adjust the instrument\u2019s force reading. Displacement calibration uses a standard ruler or reference material with a known thickness, to make sure the instrument is measuring how much the probe moves correctly. Temperature calibration for DMA is the same as for DSC\/TGA, using the same metal standards, because temperature still affects the material\u2019s mechanical behavior. We also do a \u201ccompliance calibration\u201d with a reference sample of known modulus, like fused silica, to verify the instrument\u2019s ability to accurately measure the stiffness of different materials. A lot of customers new to DMA skip force calibration, and end up with modulus values that are double or half what they should be\u2014 that\u2019s a big problem when you\u2019re designing a part that needs to meet a specific stiffness for aerospace or automotive use.<\/p>\n

Now, how often should you do these calibrations? That\u2019s a question we get all the time, and the answer depends on how often you use the instrument and what you use it for. If you\u2019re running a high-volume lab 24\/7, processing 10 samples a day, we recommend temperature, mass, and heat flow calibration every 3 months. If you use the instrument once a week, every 6 months is fine. There are also regulatory requirements: if you work in pharmaceuticals, medical devices, or food testing, you might need to calibrate before every batch of samples, and keep records of every calibration run for audits. We always tell customers to log their calibration runs\u2014even if it\u2019s just a quick indium test\u2014because if something goes wrong later, you can trace back to see when the drift started.<\/p>\n

A common myth we hear is \u201ccalibration is only for old instruments.\u201d Even a brand new instrument straight from the factory can drift slightly, especially if it\u2019s been shipped across the country with temperature fluctuations. That\u2019s why we recommend a \u201cpost-unboxing calibration\u201d for every new thermal instrument we sell. We\u2019ve had customers unbox a new DSC, run their first sample, and get a result that\u2019s 2\u00b0C off, only to realize the instrument just needed a quick temperature calibration. That\u2019s a simple fix that saves them days of troubleshooting.<\/p>\n

Now, let\u2019s talk about best practices to make calibration work for you, not against you. First, always use certified reference materials. Don\u2019t grab a random piece of indium from your stock room\u2014make sure it\u2019s traceable to a national metrology institute, like NIST in the US, or PTB in Germany. Generic materials might have impurities, which change their melting point or enthalpy, leading to bad calibration. Second, use the same sample pan and atmosphere for calibration runs as you do for your regular samples. If you use aluminum pans for your experiments, don\u2019t use a platinum pan for calibration. If you run your DSC with nitrogen gas at 50 mL\/min, don\u2019t do a calibration run with air. Even small differences here can cause drift. Third, document everything. Write down the date of calibration, the SRM used, the measured value, the adjustment made, and the results of the subsequent verification run. It takes 5 minutes, but if you ever get audited, that documentation is non-negotiable.<\/p>\n

At our team, we offer two types of calibration support for our customers. We have a full-service lab where you can send your instrument, and our technicians will perform a full calibration\u2014temperature, mass, heat flow, whatever you need\u2014with a calibrated certificate you can use for audits. We also have on-site calibration services, where one of our field engineers will come to your lab, calibrate the instrument on-site, and walk your team through how to do quick in-house checks between our visits. A lot of customers like the in-house checks: they\u2019re simple, like running an indium test once a month to make sure nothing has drifted, so they don\u2019t have to send the instrument away every time.<\/p>\n

We also host free webinars every quarter on calibration best practices, where we go through common mistakes we see\u2014like skipping the blank run for TGA, or using a reference material with unknown purity\u2014and show how to fix them. Last year, a customer from a polymer manufacturing plant told us they were getting inconsistent decomposition temperature results for their new line of biodegradable plastics. We found out they\u2019d been skipping calibration for 8 months, and their instrument\u2019s temperature was off by 3\u00b0C. After a quick calibration, their results were consistent across all their batches, and they passed their first customer audit in two years. That\u2019s the kind of impact good calibration has.<\/p>\n

If you\u2019re a lab manager, a technician, or a R&D lead who\u2019s been putting off calibrating your thermal instruments, or you\u2019re not sure if you\u2019re doing it right, we\u2019re here to help. We work with labs of all sizes, from small academic research teams to large industrial manufacturing facilities, and we can tailor a calibration schedule that fits your needs. Whether you need a single one-time calibration, ongoing service, or training for your team, we can walk you through the process, explain what you need, and make sure your results are accurate and reliable.<\/p>\n

<\/p>\n

If you\u2019re ready to get your thermal analysis instruments calibrated, or you have questions about what calibration method is right for your specific instrument, reach out to our team. We\u2019ll connect you with a technical support specialist who can walk you through every step, no matter how big or small your lab is.<\/p>\n

AMO Physics Instruments<\/a> REFERENCES<\/p>\n

    \n
  1. National Institute of Standards and Technology (NIST). Standard Reference Materials for Thermal Analysis.<\/li>\n
  2. International Organization for Standardization (ISO). ISO 11357: Plastics – Differential Scanning Calorimetry (DSC).<\/li>\n
  3. ASTM International. E967: Standard Practice for Temperature Calibration of Differential Scanning Calorimeters and Thermogravimetric Analyzers.<\/li>\n
  4. ASTM International. E1868: Standard Test Method for Mass Calibration of Thermogravimetric Analyzers.<\/li>\n
  5. Data Physics Instruments. Dynamic Mechanical Analysis (DMA) Calibration Guidelines.<\/li>\n<\/ol>\n
    \n

    Nanjing Longbow Scientific&Educational Instrument Co., Ltd.<\/a>
    As one of the most professional thermal analysis instruments manufacturers and suppliers in China, we’re featured by quality products and good service. Please rest assured to buy customized thermal analysis instruments from our factory. If you have any enquiry about pricelist, please feel free to email us.
    Address: Room D, 22th floor, No.305, North Jiangdong Road, Nanjing,Jiangsu Province, China
    E-mail: 79425380@qq.com
    WebSite:     https:\/\/www.lb-physics.com\/<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

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