Date：2019-05-31View：

STRAIN GAUGE TYPE SELECTION

For high precsion sensor and stresss testig, we recommend our compan's BHF series products. Our BHF series stain gauges use the intetatnall advanced "epoxy phenolic" material. This strain gauge has numerous advantages such as small lag, good dupicaion, stbility and inulation. For general sensors and stress analysis, we recommend SZ series, or Bx series with bar length.

ADHESIVE

For sensors and precision testing, we recommend using high temperature solidifying adhesive: H-610 glue, which has characteristic of strong adhesive force, good insulation and small creep, specially suitedfor sensors manufacturing and precision stress analysis. When used outdoors or for general testing, 502 fast dry glue can be used.

POLISH OF TEST SAMPLE PASTE SIDE

To firmly affix strain gauges, paste part of test sample shall be properly delt with. Choose 200~400 sand paper for polishing base on the material of test sample, and apply at a 45° angle overlapping stripe fromstrain gauge paste side or sand blasting. Then clean with the ultrasonic wave cleaner, or scrub away thepolish spot with the acetone lint ball until no dirt can be seen. Follow single direction when scrubbing away,do not alternately clean back and forth .

DELIMIT GLUE POSTIONLINE

In order to guarantee the accuracy of the strain gauge glue position, and truly show the strain of the measuring point, position line should be drawn on the glue, strain gauge working bar area must be avoided.Afterwarrards, clean the lest sample with acetone and dehydrated alcohol, and dry it promptly by wiping or using a dryer.

STRAIN GAUGE GLUE

Strain gauge glue has sinificant impact on testing precision of the test sample. Before using, clean the test sample with acetone and dehydrated alcohol, scour both sides of strain gauge in single direction with absolute ethyl alcohol or acetone dipped tampon, to be ready for use. Then coat the test sample pasteposition and strain gauge basis with glue, align the central line of strain gauge with position line of the testsample covered with a teflon film, and squeeze out the unnecessary glue liquid by trundling and pushingthe air bubble with your finger along the thread diection of the strain gauge. After that, don't forget to checkthe paste area, promptly handle problems such as inorect paste position or air bubble, etc.

SOLIDIFY

Presently, all commonly used adhesives need to be heated and solidied.dTemperature, time and pressure are the main factors to solidiy, relevant solidify craft criterion shall be applied for guarntee. Pad teflon film and thermostable silicon rubber board on strain gauge when applying pressure, and then use clamp to apply pressure. Amount of preesure and non-uniform stress willl cause srain gauge's resistance value to change,vaiue creep and lag wil also change. Heat and solidify as recommended, cary on stabilizing after pesuore moved, which is the second solidify.

PASTE QUALITY CHECK

Carefully check paste quality after stabilizing:

① The change of rsistance value before and           after strain gauge pasted

② Paste position is correct or not

③ Strain gauge is deformed or not

④ Whether impurity or air bubble in rubber layer

⑤ Measure insulation resistance

⑥ The paste is firmed or not

BRIDGING AND WELDING

Before welding, use sandy rubber or thin sandpaper to gently clean the residual glue liquid and oxide on spot surface, be carefull not to damage the strain gauge thread bar. Clean with solvent and ethyl alcohol,and then use alcohol resin as welding flux and weld rapidly. When bridging, it is required to place release ring on the connecting thread of the welding spot and connecting end to prevent the test sample from pressed on connecting thread as to avoid open circuit due to snap down lead. Finally clean welding flux and other residue with dehydrated alcohol and dry it promptly by wiping or using a dryer.

INSTALLED STRAIN GAUGE

Use silicon rubber like 703, 704 or D04, evenly applied on the surface to be protected, to protect the stain gauge   once the soddering and the wing is completed.

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