Bright Instruments
42
3.6.2 SPECIFIC PROBLEMS
Thick/thin sections, intermittent failure to cut:
Specimen
• Knife not sharp enough
• Knife tilt angle too high/low
• Clamping screws too loose
• Specimen loose on holder
• Cutting temperatures too warm/cold
• Anti-roll plate adjusted too high
• Tissue expansion due to block warming up
Sections crumbling or not forming:
• Freezing technique too slow
• Cutting temperatures too warm/cold
• Specimen not equilibrated to chamber
temperature
• Specimen dehydrated
• Knife not sharp enough
• Cutting motion too fast or uneven
• Knife tilt angle too high/low
Excessive compression of sections:
• Knife not sharp enough
• Knife tilt angle too high
• Knife surfaces frosted or debris built up
• Anti-roll plate frosted, too warm or
incorrectly adjusted
• Freezing technique too slow
• Cutting temperature too warm
Uneven thickness across section:
• clamping screws too loose
• specimen loose in holder
• specimen was not trimmed correctly
• knife not sharp enough
• knife edge too thin
• cutting motion uneven
Vertical score marks on sections:
• Knife edge nicked or chipped
• Knife faces have built up debris or frost
• Anti-roll plate edge damaged
• Anti-roll plate surface has debris or frost
built up
• Tissue contains hard, fine particles
(e.g. bone fragments)
NB:
When removing frost and debris always
brush up the knife, never down or along.
Sections curl over anti-roll plate:
• Anti-roll plate too low
Section curl under anti-roll plate:
• Anti-roll plate at too large an angle to knife
Sections curl under and stick to
anti-roll plate:
• Anti-roll plate too warm, greasy
Sections curl after lifting anti-roll plate:
• Anti-roll plate at too large an angle to knife
• Movement too quick
• Delay in collecting sections
• Static electricity present
Sections fail to flatten and pass down knife:
• Anti-roll plate too warm, greasy or
misaligned
• Knife surface has built up frost or debris or
is too warm
NB:
To remove static electricity use an anti-
static brush or gun. The main area of static
electricity build-up is on the anti-roll plate.
3. Cutting & Collecting
Sections Cont.
