Blockers are tools that help you to temporarily apply an adhesive pad and “block” to the front of a lens that is about to be cut to fit a frame. The adhesive pad or “leap pad” holds the block which is designed so it will only mount in the edger in the correct position for cut-out.

Much like edging, blocking can be done by hand. You do not need a blocker to attach a block to the front of a lens with accuracy. You do need a blocker if you are going to attach many blocks, to many lenses, in a consistent and timely manner. A basic manual blocker will work very well for almost all finishing work. Labs that produce high volume and specialty grinds will require high-end blockers.

Santinelli’s CE-9 manual blocker
Santinelli’s ICE Mini 3 Blocker This blocker has an edger interface which allows the job data to guide your blocking and will auto-enter the job in the edger.

Here are blocks attached to lenses that are about to be cut. Notice all the notches and raised areas designed to keep the block and lens aligned during cutting.
Look inside the circle and you can see the block being pinched between the chuck and the lens. This lens is now held in place so it can be cut and remain aligned for shape and the prescription.

AR or non-glare coatings can be so slippery that a lens can slip when being ground. The industry is working on solving the problem from many different approaches. Edgers may have a “soft” or “slow” grind which reduces slipping. The lenses may have a non-slip coating. There are also different blocks, leap pads and adhesive pads all designed to reduce the risk of spinning lenses.

Do not attempt any home-grown remedies like hairspray or increased chuck pressure beyond what is recommended.

With trial and error you will find a combination that works well for your edger and lens types. Your lab may have suggestions on the best approach to use.

Edging requires what are called “consumables.” Every lens run will require a leap pad. Every AR coated lens will require a leap pad, riki pad and often a protective pas as well. Soft, pliable blocks will wear out over time.

Blocks: Softer pliable blocks will reduce slipping.
Leap or blocking pads: These are the pads that hold the block to the front of the lens.
3M - hires
Backing or “Riki” pads: These pads go between the leap pad and the front of the lens & may also go on the back.
Protection Pads: Are cut to shape from a large roll and are used to protect the lens during edging, hand stone, polishing, drilling etc.