Introduction: 3d Printed Medical Vein Finder

Hello there.My name is Alex , I am a military automotive engineer and my girlfriend is a registered nurse . Her job task is to take blood samples for further analyses from patients of all ages ( especially young ) . Her first day at her new job wasn't that great because she wasn't that experienced in finding veins, and while she complained, i googled up some solutions. Vein finders are common in western countries but here they are too expensive for us ( 100-150£ for one vein finder , and her income was standing at 200£ per month ) so i decided to make one myself .I found some ideas , articles but no instructions ( the one in Kenya for example) and then i found this link , but as a patient , i wouldn't want my nurse to use that on me because of its appearance. So I designed a whole series of them in the attempt to make it more patient - friendly , and i finally succeeded. I also made it in a way not to warp when printing with PLA , using blue tape , rubbing alcohol and the heat bed not active because i assumed it would be printed in areas that are poor and a printer with a heated bed would be more expensive .
Also this can be used in various countries around the world where they don't have medical equipment or money to buy it or professional staff is scarce . Now with the Zika virus , malaria and all sorts of diseases ... it's a helping hand.

How does it work. Well , light at 620-680 nm penetrates skin, fat tissue and oxygenated blood with ease but when it meets de-oxygenated blood ( what circulates trough the veins ), it gets caught up in there , thus resulting in a dark area. You will have to put the device on skin , search for a proper vein , aim it , and put the needle in that gap , in the vein. Very useful when working with anxiety suffering patients , children , patients that may cause them a drama if you try 2-3-4 times to get a sample of his/her blood.(btw sorry for my English).

Step 1: Materials

For this project you will need the following

- 3d printer with darker filament ( i tested green , purple and yellow , purple was the best , yellow the worst, green was ok )

- soldering iron and lead

- dremel

- on - off switch link

-1 M3 bolt ( not that long , 5-8 mm should be enough )

-1 M3 metal threaded insert link

- battery contacts for 2 AA batteries link

- 2 AA batteries( not in the picture )

- wire link

- 1 medical needle from a syringe

- 1 tweezers

- 1 nail cutter

- pliers

- glue

- caliper

- 10 cm of shrinking tube link

- about 15 resistors at 51ohm ( should be ok between 45 and 75) link

- about 15 red LEDs wavelength above 620 nm and not higher than 680nm because you won't be able to see the light at all and between (edited after more testing) 5000 and 6500mcd ( not higher it will have the same effect as facing a car with headlights on coming at night from the opposite side of the road and you won't see the veins, not lower , it won't enough power to penetrate skin efficiently the veins) link
EDIT: I did not use 15 leds or resistors only 11 of each . I stated 15 so that if some people wire the leds wrong and burn them , they would have a spare and not wait another week or so for resupply.

I used and you will find all the items required over there with ease . It's a great polish website , delivers all around Europe .

Step 2: Printing

Here are the files. It took my like 3 months to figure it out how to make it better. Now is safe to work with it..
It takes about 4-5 hours with sunhokey 2015 to print .
Use dark colored filament , I tested with yellow , purple and green . Purple was the best , green was ok , yellow was useless .

Download files from here (Zortrax library)

I used 0.25mm layer height because I want it done fast, if you want , you can get it done at 0.1mm , and it will look like out of the factory.

I used Catia to design it.

If you don't have a 3D printer , you can buy the prints from shapeways.
lid -
USE PLA as it's not toxic , don't worry , it won't break if you drop it , i made some design features to increase its strength.
Also. Lay down the blue tape , stick it well with a card ( i used my pharmacy card because I don't use it very often ) eliminate the bubbles under the tape. Spray your tape with alcohol ( 70-80%) but not much to soak it . let it dry for a minute then start your print but before you stat your print , click to make the brim about 12 mm wide. It works. You can use any method you like , hairspray and glass , or kapton tape , the choice is yours.

Step 3: Preparations(1)

While the printer......prints , your LEDs need their skirt trimmed . the hole in the vein finder is slightly larger than the diameter of the LED so it does not move around ( i had some problems with earlier models . trust me , you want your LEDs to sit put. )
Use your dremel and a sanding tip to trim them.
5.52 mm initial diameter down to 4.81mm ( hole diameter is 5mm )

Do this for all your 15 LEDs

Step 4: Preparations(2)

Second . When you want to solder the LED and your resistor , you will have to work in a veeeeery tight space ( in order to make the device usable in daily life , i had to shirk it . so ...while my girlfriend tried her needles on me with a earlier bulky model , i had an idea . why not wrap one end of the resistor around the needle , pull it put , and then solder it around the LED? ( the soldering part comes after placing the LED in the 3d printed body )
Do this for all your 15 resistors.

Step 5: Finishing the Printed Body and Mounting the LEDs

But first , we have to remove the printed body from the printing table . Btw , I usually use blue tesa tape + rubbing alcohol . it sticks so well that it's annoying to remove , and then , I use dental floss , peal the skirt a little , then put the dental floss underneath and get that print out of there. Then , we must polish the LED places from underneath as blobs may get formed during the print.
Then , we must mount the LEDs . The LED has a longer leg and a shorter one . Put the longer legs closer to the center , and the shorter legs outwards.

They will be connect as the diagram shows.

Step 6: Soldering 1

Bend the longer legs with the tweezers and solder them together.

Place the resistors like in the pic on the outer ring (the shorter legs) , solder the resistors to the LEDs and then cut the extra length of the leg with the nail clipper . Place a 3-4-5 mm shrinking tube at the LED-resistor area , and shrink it with your soldering iron ( that's how i do it ).

While the soldering iron is still hot , place your metal insert above the hole and gently push it down.

Then , solder the resistor legs one to each other. it should look nice like in my pic.

Step 7: Soldering 2

Place your battery contacts afterwards and bend their tail inwards . I lock the contacts in place melting the plastic around it with my soldering iron but you can glue them . Solder the negative pole of your batteries the outer ring . Solder one 5 cm wire to the inner ring , pull the wire trough the switch gap , and the other end solder it to the switch on\off . Another 5 cm wire to the positive pole, pull it trough the hole and then solder the other end to the switch. I recommend you should isolate your switch legs with shrinking tube , and that you should place one 5 mm shrinking tube on the wire from the inner ring and from the positive pole before soldering the wires to the switch . Mount the switch into place. Mount the top plate into place and glue it shut.

Step 8: Finish

It's done. All you have to do now is get some batteries , place your battery cover and close it down with the M3 bolt.

If you have any questions , please send them to here : either ( my gf ) , or ( myself )

Step 9: Using the Vein Finder

You light it up , put it on the pacient's arm perpendicular to the vein's direction , find a good vein , flip it paralel to the veins and put your needle in that U gap . Simple as that.

3D Printing Contest 2016

Grand Prize in the
3D Printing Contest 2016