“Digi-Peca” Saves Time When Changing Materials

“Digi-Peca” Saves Time When Changing Materials

In previous articles, we have examined situations involving only one injection machine. Of course, in most plants there are multiple machines in operation. When considering material feeding for a row, or a whole plant full of molders, different approaches become necessary. For example a centralized, automatic feeding system is a logical step over individual loading systems. But some people may hesitate to pursue this concept because of the high initial investment.

In this article I will introduce a centralized resin feed system incorporating the “Digi-Peca” a wireless line purging system. The Digi-Peca makes central feed systems cheaper, and more flexible.

Let’s look at the example in the next figure where 4 injection machines are running. We can see problems happening during material changes.

As written previously, the on line set-up increases down time and costs, and leads to a decrease in output. The off line set-up does not increase down time, but does increase indirect costs.

I will explain in more detail the problem shown in the table above. Please take a look at the next figure. You can see, between the injection machine and the dryer, a material feed hose, vacuum hose and signal cable for the level sensor at the injection machine.

When we switch the dryer to change materials, we must change all the connections as well. This causes problems ① and ② in the table above.

By using the Digi-Peca Line Purging System the injection machine and dryer can be changed more quickly and easily. There is no vacuum hose or signal line between the injection machine and the dryer. There is no need for the signal line at all. So we can eliminate problems ① and ②.

Let’s talk more in depth about the Digi-Peca Line Purging System. The Digi-Peca is comprised of a switching section and a controller section. The switching mechanism is vacuum activated. When vacuum pressure builds inside the feed line as the vacuum loading pump runs the switching section is activated. The controller then opens the push damper valve, dosing material out for feeding. Material flows into the feed line where it is drawn away by the loading system. The push damper then closes after a set time. Material conveying stops after the push damper is closed. The loading pump continues to run for a time, insuring there is no material left in the feed line.

Let see how a 4-injection machine system looks like when we use the Digi Peca Line Purging System. The figure below show the system with the Digi-Pecas.

When changing materials, only resin feed hose connections need to be changed.
There is no need to move the dryers around on the factory floor. Also, all the jobs can be done in one location by using the connection unit as shown in the photo below. The connection unit can is clearly visible at the connection box.

In the “Digi-Peca Line Purge System” problems ①, ②, ③, ④ are eliminated. If time lost on problems ① and ② was taking 0.5 hour, and there were 500 material changes a year, we estimate that production time will be increased by 1,000 hours a year! Additionally, we can eliminate the need of moving the dryers around the factory. Moreover by the enhanced visibility and ease of use will prevent mistakes, which is another great advantage.