How bleeds get trimmed?

I never worked for a printing company so I dont know how they cut print job that contain bleeds.
Do printing companies equally trim bleeds on all sides, or do they only trim on two sides, say left and bottom, or top and right...etc?

For example, sometimes when my business cards come from a printing job, I notice way more edge was cut off from the bottom than the top. Sometimes this makes it harder to position elements when the bleed on one or two sides was cut deep.

Can someone explain or confirm this?

Thanks, Ben

 

A lot depends on the print job itself and how its going to run through the equipment. The name of the game is to do as less as possible but get the desired results. A true bleed will be trimmed all sides, but if it bleeds side to side and run together when one cut is made it is a true bleed on both pieces.

 

Let's say you're working on cutting (or setting up for print) a business card.

Background of the card is a solid color:
When imposing or stepping the file (layout of multiples on a sheet) you may choose to only have a bleed on the cards that border the outside. All cards in the center will be butted up against each other so that one cut can be made.

Background Varies:
If a card has a photo or inconsistent background you MUST bleed all sides when stepping. Usually a 1/8" space is placed on all sides of the art. When imposed this create a 1/4" space between each card and twice as many cuts must be made to trim each card.

If you find your cards are cut heavy to one side (they shouldn't be)
The cutter may not be doing his job properly. He should start from the center of the stack and work his way to either side.
this will minimize visible error by half. No cutter is ever perfect, cards with borders or frames will often show this error more than cards without them.

 

With a manual cutter this method of cutting is common. With a programmed cutter, I think its more likely
the person will put the cards in lead edge 1st (all cards should be same distance from edge fed into press or printer 1st. Then the program is used to step and repeat to the cuts which minimizes error. The difficulty in any of these is the original press or printer must be set to print at the proper location centered on the sheet.