I remember as a young lad watching a magician making a dollar bill disappear or a paper clip levitate. The power of illusions.
An injection molding company was having issues in removing their parts from a tool. This company made plastic spoons in a multi-cavity tool. During the start of the operation, they noticed that some of the spoons (reference photo below) were “sticking” to the mold surface. Some spoons looked like they spoon were “defying gravity” . It was not an illusion of levitation, but static.
Static charges can dramatically slow down production rates with plastic materials. In this instance, the operator had to remove the spoons manually prior to restarting another cycle on the machine. They measured roughly 30% of the time that they would have to stop their operation. To counteract the parts sticking, they attempted to mount a pipe with drill holes above the tool. They tried to use the force from the compressed air to remove any stragglers that remained in the tool. This is a simple and easy-to-do method; but with this type of blow-off, it is very loud, inefficient and not real effective.
They only saw a slight improvement in part removal as they still had to stop roughly 28% of the time. The bottom portion of the cavities still had spoons remaining in the tool. With the amount of money being lost from slow production rates and the possibility of tool damage, they decided to contact EXAIR.
In today’s injection molding market, tool coatings are commonly used to extend tool life and increase lubricity. When a buffer is placed between plastic parts and the tool surface, static can be generated and become a real issue. With the company above, the spoons were sticking in different areas of the tool depending on the static buildup. If they can neutralize the static charges, then the spoons cannot defy gravity.
I recommended our model 112212 Gen4 Super Ion Air Knife Kit. The Gen4 Super Ion Air Knife is designed to efficiently blow air and to carry both positive and negative ions to remove any kind of static charge. For this model, it comes with a 12” (30.5 cm) long Super Air Knife with a Gen4 Ionizing Bar attached. With the compact and lightweight design, it could easily be positioned above the tool to operate. The kit also includes a power supply to power the ionizer, a filter to clean the compressed air, a regulator to control the force, and a shim set to modify force changes. This complete kit had everything required to begin operations to remove static.
The customer only had to attach the unit to a compressed air source. Once they started using the Gen4 Super Ion Air Knife, the removal rate of parts went to 100%. As an added benefit, when the drilled pipe was replaced, the noise level dropped as well as the compressed air usage reduced. By adding an EXAIR Gen4 Super Ion Air Knife to their process, the production rate was now maximized.
Static within injection molding processes can cause crushed parts, slower production rates, and even more costly; tool damage. If you believe that static is causing things to “defy gravity”, EXAIR has a great range of Gen4 Static Eliminator products to remove that “magic” force. And, for the company above, they didn’t have to continually watch their money “disappear”.
John Ball
Application Engineer
Email: johnball@exair.com
Twitter: @EXAIR_jb
Photo by: Magic Hat by KCADRC. Creative Commons CC0.