Hardened backing plates are required under all pads that bottom out. 最底下的那块垫板后应该加一块热处理背板。
This test method is not intended for use in testing corrugated boxboard, liner board, or hardboards that tend to cut the thin rubber diaphragm. 这个试验方法不用于试验割成薄的橡胶横隔膜的瓦楞盒纸板，垫板或硬纸板。
