Department of Mechanical Engineering

The stent was introduced to replace the traditional invasive surgery and angioplasty balloon that was used in treating cardiovascular disease. In the early stage of angioplasty, cardiologists used a balloon to expand the artery that was clogged. However, in some cases the wall of the coronary artery became weakened after the balloon is dilated, resulting an acute or sub acute collapse of the artery. The modern stent was conceived in the 1980s in response to the danger posed by the angioplasty balloon. The stent was able diminish the danger of collapsing artery wall, but it gave birth to the problem of restenosis. After years of engineering and designing, the stent is equipped with biocompatible and radio visible coating which reduce the chance of restenosis.

During the manufacturing process when the coating solution is applied, some of the solution can overflow onto undesirable area, the inner diameter. Our goal is to design a coating overflow removal tool that is easily operated by one person and each cycle time should be around 2 minute. Our engineering requirements is that it should remove as much overflow from the inner diameter as possible without damaging the stent and the drug coated on the outer diameter. The removal tool should be able to work with a range of 8-28mm in length and an inner diameter of 1.37 mm.

Figure 1.1 3-D Illustration of a Drug eluting stent expanded to hold open an arteries.

The final design SolidWorks is shown in figure 1.3, and prototype is shown in figure 1.4. The important components are the slider crank mechanisms, linear shafts and supports, stent slider, toggles clamps, and brush-mandrel. The devices main function is to push the stent over the brushes located on the mandrel by utilizing the linear motion produces by the crank shaft mechanism. (Click Here to See Clip of the Assembly)

n1.) The stent will be loaded onto the mandrel by the operator.

n2.) The operator will slide the mandrel into the slots of the stent slider making sure that stent is placed in between the opposing faces of the slider.

n3.) The mandrel is clamp down on both side.

n4.) The slider crank will move the stent slider back and forth.

n5.) The stent will in turn be pushed by the slider over the mandrel’s brush.

Evaluation

n1.) Cleans the overflow solution on the inner diameter surface of the stent.

n2.) No surface contact with the outer diameter of the stent.

n3.) No physical damage to the stent or to the surface coating.

n4.) Operated by one person.

n5.) Less than two minute cycle time.

Cost and Manufacturing Time

Parts Description	Quantity	Vendor	Price Each	Total Cost
Motor	1	MC-Master Carr	$180.00	$180.00
Rubber Wheel	1	MC-Master Carr	$30.00	$30.00
Teflon Bar 2"x4"	1	MC-Master Carr	$73.16	$73.16
Alunminum Bar	1	MC-Master Carr	$84.85	$84.85
Aluminum Sheet	1	MC-Master Carr	$44.38	$44.38
12" Bronze Bar	1	MC-Master Carr	$13.54	$13.54
Brushes/Mandrel	3	Gordon. Corp	$0.00	$0.00
Miscellaneous Parts	28	MC-Master Carr	NA	$138.23
Total Costs				$564.16

Custom Parts	Manufacturing Time (hr)
8" Circular Arm	3.2
Circular Arm Support	4.25
Slider Support	2.2
Slider Sides	3
7" Crank Arm	1.5
Shafts Support	3.25
Clamps Support	2.5
14" Steel Shaft	0.5
2.7" Drill Rod	0.5
12"x18.5" Base	6
Motor Mounting	2
Motor Shaft	0.5
Miscellaneous	5
Total Manufacturing Time :	34.4 hours

Special Thanks

Dr. Thomas Stahovich

Instructor ME 175 A,B,C

Mark Abushabky

Liaison at Guidant

Paul Stovall

Department of Mechanical Engineering, Machinist

God The Almighty