Improving the Efficiency of the Blender - blade remodeling

The bicycle blender that was tested in the spring of 2013 was only designed to blend soft fruit, juice, and yogurt (or foods with similar consistencies).  Even with very soft foods, the blender still left chunks of food.  Ideally, the blender will be able to blend harder foods more thoroughly. 

There are three widely accepted features of good blenders; jar shape, number and position of blades and motor strength.  To improve the efficiency and functionality of the blender, the primary focus will be on improving the blade and being conscious of a good jar shape. 

Our current blade design is a single strip of sheet metal that is curled on the ends.  The flat part of the blade is positioned approximately 1 ½ inches from the base of the pitcher, and the bottom of the curls are approximately ½ an inch from the base.  Additionally, the outermost edge of the blade is approximately an inch from the side of the pitcher.  The blade does not have a very large reach, and thus requires a lot of pedaling which still does not produce a smooth blend.  In order to improve the quality and functionality of the blender, a new blade design must be developed.  

Current blade design

Number and position of blades-

The length and configuration of the blades plays a larger role in the performance of the blender than the number of points at which blades came in contacted with the blended matter.  To maximize efficiency, blades should be angled differently, and there should be a minimal distance between the sides of the jar and the end of the blade, ¼ of an inch is optimal.

The primary focus during the remodeling process was the shape of the blade.  The main problems with the shape of our current blade is that both ends of the current blade point in the same direction, and that there is a full inch between the edge of the blade and the side of the pitcher.  Both of these factors significantly detract from the efficiency of the blade by limiting the area the blade can reach.  The best blades have four prongs, two of which are angled up and the other two are angled down; however, it was also important to be conscious of how difficult a particular blade would be to manufacture. The benefits, increased cutting reach and efficiency, of a four-pronged design outweighed the additional difficulty to manufacture.

Remodeling options

Pugh chart

What was done to make the new blade:

-       3” by 3” cut out of thick sheet metal,

-       Cut the square into an X shape so that the legs of the X are ½ an inch wide

-       Drill a ¼ inch hole in the center of the X

-       Sharpen each edge of the X by sanding with a Dremel tool

-       Shape the blade by bending each prong approximately 45 degrees, alternating the direction of the bend

blade cut out

Folded Blade

The next step is to develop an easier method of holding the blade in place.  The current method of bent piano wire is very difficult to work with and can compromise the structural integrity of the blade.  Additionally, the piano wire may rust.