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Mechanical system

  1. May 24, 2007 #1
    Hi, I'm new to the site. I posted this question in another thread to no avail, so I'll try starting over with a new one of my own. I am doing research on tattoo machine mechanics and this came up in Google. It is very interesting, so here I am. I don't have a lot of technical knowledge regarding any of the systems at work here, but I do have a general idea based on what I have been reading. Tattoo machines have a lot going on when in operation. They have an electrical system, a magnetic system created by the electrical system, and a mechanical system that is operated by the magnetic system. I am fairly intuitive and can learn almost anything. I am fascinated with these machines and want to be able to build my own. I have done a few rebuilds and have run into some issues that I need some technical assistance with. I have a few different questions, but I'll try to work them out one at a time so I don't get any more confused.
    The basic function of the machine is to place tattoo ink into the dermis of a person's skin. Different people have different skin and the required needle configurations differ as well which require different amounts of force to accomplish this. The machine must generate enough force to drive the needle configuration into where it needs to be. Also different skin types require different amounts of force and different depths of needle travel. The taper of the needle tips are also a factor. For example a single, long taper needle does not require much force to go into thin skin. On the other hand it takes much more force to drive 13 short taper needles into tough skin.
    The electromagnets of the machine use electricity to create "pull" on the steel armature of the machine. The needle configuration is attached to this armature so as to move with it. The distance of travel, or stroke, is determined by; the bottom gap (space between the armature and the magnet surface) and the amount of front spring compression. A rear spring attached to the base frame of the machine applies force to the front spring and is used to counteract the magnetic pull. At rest, the front spring is compressed against the electrical contact completing an electrical circuit used to power the magnets. When you step on the foot switch and apply voltage to the circuit, the magnets pull the armature toward them releasing the front spring compression until the circuit is broken as the front spring leaves the contact point. This begins the "open" part of the oscillation. The armature continues to the magnet surface form inertia until it hits. The rear spring then takes over and returns the armature to the contact point, ending open contact time and beginning the "closed" part of the oscillation. The front spring compresses against the contact point from inertia and then the magnets pull it down again for the next oscillation. This happens many times per second, most machines run between 100 and 150 hertz. The balance between open and closed contact time results in the machine's duty cycle, which is critical for a well running machine. This duty cycle is a relationship between bottom gap, contact point gap, and front spring compression, which also equal the stroke of the needle. The weight of the armature, the stiffness of the rear spring, the needle configuration, and skin type are all factors in how much pull is required.
    My first question is how to maximize the efficiency of the voltage used to power the magnets. Standard magnets are made by taking 1" or 1-1/4" lengths of 5/16" or 3/8" diameter 1018 low carbon steel rod, insulating it with a thin layer, putting ends on it to form a spool and winding 24 or 26 gauge magnet wire around it, 8 - 12 layers thick. I am currently planning on making my own coils and am hoping to get some insight into how to maximize the efficiency of the voltage in the coil. What effect the diameter and length of the steel and the gauge and length of wire have on how the electricity is used to create the magnetic pull???
    I realize that this may be menial to some of you, but any comments on this are greatly appreciated. I have been digging for this type of info all over the web, but am having a hard time finding exactly what I need.
  2. jcsd
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