Drum feeders are one of the machines that supply small parts in automated or mechanized production. You can fill a drum feeder with unoriented bulk products, and it will orient and feed the products.
While drum feeders are not as common as bowl feeders, they are still very usable for simpler parts. In this project I will share some of my endeavors in making drum feeders.
Files
HPDF drumfeeder files.zip
The stl files of the drumfeeder, shared with the knowledge that these will only work with the very motors used and for the very pins and springs that this drumfeeder was designed for. Any alterations have to be made by the user using the below STEP files
x-zip-compressed -
352.02 kB -
10/17/2020 at 10:08
Th primary reason I built this is to speed up the assembly of the HP45 connector. I need to answer that question, did I?
Yes, quite significantly. I timed making the connector by hand and with the feeder. By hand it takes me 5 minutes to place all the pins, and 10 more minutes to place the springs. The springs tend to get tangled in each other.
With the feeder it takes me around 5 minutes. 2 minutes for the pins, and 3 minutes for the springs. The constant tumbling separates the springs. Below some videos of me assembling by hand and with the feeder.
(I really need to lock the focus when I am shooting this. Also, a camera on my hands significantly lowers my dexterity)
There is plenty room for improvement left. The feeder with a vibration motor is really not ideal. Working with an electromagnet is more common, and something I want to try. Also I want a separator. Right now I have either a waterfall of parts, or I am waiting 10 seconds on a part. I also want to easily remove the drum. Right now it is bolted in place, and hard to empty. All of these are food for the future.
With the drum attached, everything is working on the drum feeder. Below are 3 videos. 1 of the pins being fed, 1 of the springs being fed, and 1 of the springs being fed, but with a chute at the end.
The videos also include some shots from the inside of the feeder. Normally speaking you would need 2 different linear guides for different products (and maybe even different drums) but the springs and pins share a lot of the same dimensions. In the next log I will share a side by side view of assembling the connector. One by hand and one with the drum feeder.
Here is my first attempt at making a linear vibration feeder using (you guessed it) a simple vibration motor.
There are 2 main components to this feeder method. The spring arms, angled at 15-30 degrees, and the vibration motor. The angle insures that any movement right is always accompanied with a movement up (increasing friction) and left is always going down (decreasing friction). The vibration motor is mounted to the top and provides the force to sway the springs left and right. A track is mounted to the top of the spring.
I do want to experiment with a feeder using an electromagnet, but for now, this has worked surprisingly well.
A drum feeder generally consists of a few basic parts. For this introduction I am going to use the first usable video I can find on Youtube.
Drum
The first part of a drum feeder is, you guessed it, the drum. The drum agitates the parts and ribs in the drum transport parts higher into the drum. The parts are then dropped onto the next part of the drum feeder.
Linear track
The next part is the linear track, or the 'feeder' part. This can be a belt, but is more often some sort of linear vibration feeder. A vibration feeder works adding a vibration motor or electromagnet to the top of a shape like the one shown below. The bottom of this shape is firmly fixed. The angled ribs only allow the top part of the block to go up and left, and down and right. The friction while moving up and left is higher than the friction moving down and right, meaning the parts will go to the left when it is vibrating. I will show some prototypes and detailed workings later in this project.
There is a little bit more to it, with resonant frequencies and masses, but that is the basics of it. It is important to include a lot of mass on the stationary side of a vibrating conveyor. If you don't, both sides will vibrate an equal amount, and the linear feeder won't feed (I already had this in my experiments).
On the top of the shown block there is a track for the products you want to feed. This track has shapes built in that block badly oriented parts and drop them back into the drum. All the correct parts will then continue down the track, to the next part.
Separator
The last part it to add a separator or some other kind of tool to the end. Else there will just be an endless stream of products coming out of the feeder. Separators are a whole different story I won't be delving into right now. I will be using simple chutes for the first few experiments.
Alternative title: "Why on earth would anyone need to build a drum feeder"
I have a certain connector I use for one of my projects: https://hackaday.io/project/86954-oasis-3dp. This connector consists of a plastic body, 52 gold plated pins, and 52 springs. I get all of these parts separate, in bulk. Lets assume for sake of argument that this connector cannot be bought assembled (read, I already have 125 unassembled).
It takes 15 (miserable) minutes to assemble a connector by hand, with tweezers. Of that 15 minutes, it takes 5 minutes to place the pins, and 10 minutes to place the springs. The springs tend to lock in each other, and it takes time to take them apart. With 125 connectors to be assembled, I have at most around 32 hours to automate this process, minus whatever time it will take afterwards.
32 hours it not much for this type of development, but I am also curious to develop these tools. I think that if I can develop it now, it will take me much less time in the future (and hopefully some other people too).
I can't help but think "Next, on How It's Made"... these kinds of assembly automation tricks are among my favorites!
Can't wait to see how you solved this. I can't quite envision how this get automated? Do you still have to place each spring by hand, but this separates and orients them saving the fiddly bits of it?
I still need to catch up on some writing that gives the details.
The way I have it constructed the drum feeder it is feeding a steady stream of springs or pins into a chute. I hold the connector under the chute, and the pins or springs drop into the connector. Sometimes I have to wait seconds on the next part, sometimes I get too many and the excess drops into a bin below.
I have already timed it. By hand it took 15 minutes, with the feeder it takes 5-6 minutes. Most of these savings are in fiddling with the pins and springs, and getting springs separated from each other.
Fully automating it will take in the neighborhood of 250-500 hours, so I will leave that for another time.
I hope to post the comparison video soon. That will clear a lot of it up.
I can't help but think "Next, on How It's Made"... these kinds of assembly automation tricks are among my favorites!
Can't wait to see how you solved this. I can't quite envision how this get automated? Do you still have to place each spring by hand, but this separates and orients them saving the fiddly bits of it?