Showing posts with label Molding. Show all posts
Showing posts with label Molding. Show all posts

Wednesday, November 24, 2010

On Site Molding Advantages

By Susan Kenny, Business Unit Coordinator

In 1999, Plastic Design Inc. helped their customer, at the time Edwards Systems Technology (EST) - now GE Infrastructure (GE), set up an on site molding division. This was a big step for both companies.

They started with 4 all electric Niigata molding machines ranging from a 55 ton to a 200 ton press, a few molds and 3 materials. It was staffed with three shifts. Two people per shift with first shift having a third person to clean molds and make small repairs. Within a year Niigata was added to the cell (this time a 385 ton press), a couple of robots, a few more molds and a couple more materials.

The advantages of having the molding machines in the building were starting to shine through:

Inventory levels were going down, no transportation costs for moving molded parts.Packaging costs were near nonexistent. Totes were replacing some of the corrugated boxes. Boxes were being reused over and over again.Molded parts were going straight to the floor, no more incoming inspections, quality measurements are done every two hours and all QA records are held on site. Parts were being handled much less. The on site molding division started taking over subassemblies which freed up space for EST/GE to start new product lines.

But these are the things we expected to happen when the project started. What were the advantages that weren’t right there in front of them when this idea came about? I don’t know about you but in the morning while I am riding to work I get in work mode. I am constantly thinking about how we can improve this or that. Now, normally when you have an idea on a part or project that is sourced to you, you have to email or call and send prints and give them time to look at what you’re talking about and then wait for them to get back to you, by then the excitement is gone!

Let me give you a couple of for instances. An Engineer with an idea or need comes down. We put the mold on the bench, open it up, look at a part, look at the mold and solve the problem or come up with an idea of how to make a change or improvement that needs to be made. Brainstorming time cut way down. No leaving messages and waiting to hear back!

Another for instance, the end user for a part doesn’t think the packaging is user friendly. That person sees me in the hall and says hey, can you look at this for a minute? I go to their station find out what it is that they would like to change to make it more user friendly for them, then go talk to the supervisor of the line see what we can do to make it work for them. This instance it was that the box was too heavy, so we put fewer parts in the box.

You can see that people from all aspects of the company have input. Some people might not ever bring up an idea they have because they might not know who to go to or what could be done to fix it. But, they see me and they know I am the manager of the mold shop that their parts are coming from and they ask what if, or hey, can ya? After nine years, ninety plus part numbers, fifteen or so materials and adding 14 more people to the crew, we have formed a bond with our customer that in my opinion cannot be replaced! We work together as a team, we problem solve together. We find ways to save money together and we make each others jobs easier and less time consuming. Parts are not late; lines are not down because someone forgot to order. We are down the hall and to the right.

I asked a few of the people I work with everyday at GE to give me their opinion of having on site molding and the advantage of it, here is what they wrote:

I do like the fact that there is no middle man. I can get my parts when I need them and there is no need to wait around for some sort of confirmation if the parts have been shipped, or have to wait around for the buyers to get a hold of the suppliers to see what the situation is. I can pretty much just go down the hall and get it myself! :) -Tanya Thompson, Material Handler, GE Security

Having the molding on site has helped us reduce our inventory and better service/quality. PDI on site has been very accommodating and is greatly appreciated. - Deborah Bagley, Production Supervisor, GE Security

Having on site molding provides reduced inventory levels, lower cost products, quality parts, fast delivery, and a wonderful partnership - Les Archer, POURS

My opinion as a Manufacturing Engineer is that having the molding on site is great for quality and making engineering changes. The problems that occur usually can be fixed within 24 hrs and all of the support need is very close at hand. This makes great use of demand flow lines and excellent quality for products. - Wendy L Rolfe, Process and Manufacturing Engineer

Now, my opinions of the advantages of being an on site molder: The biggest advantage for us as an on site molder is that we learn a great deal about the parts we make for our customer, what the most important characteristics of the parts are that we are supplying. How these parts are assembled together, how parts function within the product. In my opinion if we were not right here being a part of their daily operations we would not have this advantage. We are right here by their side trying to make their job and our job easier and more efficient by taking out the waste in a process. Being an on site molder has given us such a clearer picture of what we need to do to stay on top by adding quality, service and convenience. I don’t think anyone ever thought of all the possible advantages in the very beginning. This is true teamwork with no star players. We work together to make quality parts! ----------------------------------------------

Plastic Design International was started in 1977 in the short-run prototype R&D business. PDI is now one of the most effective Plastic Injection Molding production companies on the East Coast and an expert Mold Making manufacturer. Please contact us with any questions at 860-632-2001.


View the original article here

Plastic Injection Molding Capabilities

Our experienced tooling department personnel use their decades of combined experience to ensure the most precise tooling results available. For plastic injection tooling and prototyping applications, we meet your quality demands as well as those of your customers.

Prototype & Multi-Cavity High Production ToolsDomestic ToolingAsian ToolingProficient and Highly Skilled Tool DesignHydraulic Core pulls, cam activated, unscrewing3D Machining / CNCEDMQuick Turn-around Mold ChangesMold Sampling and EvaluationProduction support/maintenanceEngineering changes – design & implementationInnovative fixturingSolidworks----------------------------------------------

Plastic Design International was started in 1977 in the short-run prototype R&D business. PDI is now one of the most effective Plastic Injection Molding production companies on the East Coast and an expert Mold Making manufacturer. Please contact us with any questions at 860-632-2001.


View the original article here

Tuesday, November 23, 2010

Four Injection Molding Variables

From Jake Tuczapski, Process Engineer, PDI

The successful plastic part is the combination of :

Proper Part DesignMaterial SelectionTool DesignOptimized Process

Injection molding machines have a number of machine control options which affect the polymer as it moves from container to mold cavity. These include:

Barrel TemperatureHydraulic PressureHydraulic Flow RateOil TemperatureFunction timesClamp Force

Process optimization and troubleshooting are easier when you understand how machine variables affect the four injection molding variables.

Plastic Temperature Plastic temperature or melt condition is determined by a combination of barrel temperatures, screw design, screw check valve design, screw rotation speed, back pressure and residence time. Plastic temperature should be checked using a calibrated pre-heated pyrometer placed into a purge puddle that was taken on cycle. Machine temperature controllers must be properly calibrated and tuned. Screw recovery time should be monitored for consistency

Plastic Flow Rate Plastic flow rate is measured in seconds from the start of injection until transfer to pack/hold at 95-99% full mold. This fill time is not the same as first stage timer setting. Fill time in combination with calculation of shot volume gives a volumetric flow rate which is a plastic variable measurement. Plastic flow rate determines plastic viscosity as it enters the mold cavity. As the plastic molecules flow, they untangle and become aligned. They take up less space and slide easily past one another thus reducing the viscosity of the polymer melt. Because of this unique and direct relationship of fill time to plastic viscosity, fill time must be maintained shot to shot and run to run.

Plastic Pressure Plastic pressure is defined as a measure of the amount of compression of the polymer in the mold cavity at the end of the molding cycle. It is necessary to control both the amount of polymer put into the mold and the amount of polymer maintained or held in the cavity until the gate has frozen. The key machine controls that determine plastic pressure are pack pressure, pack time, hold time. The best method of measuring plastic pressure in the molded part is to use cavity pressure transducers.

Plastic Cooling Rate/Time Plastic cooling rate and time will affect final part dimensions, part appearance and cycle time. The mold surface temperature affects part aesthetics and part performance by affecting the thickness of the oriented layer of plastic molecules. When the mold is filled with plastic, most of the heat content of the melt must be transferred to the mold cavity and ultimately away from the molding area. Some heat is lost by radiation but most is removed by forced convection through the cooling channels in the mold. Heat transfer can be optimized by having turbulent flow in all cooling channels, by keeping cooling channels free of scale that insulates, by directing coolant flow to the most needed area and by keeping the plastic against the cavity surface as long a practical. Compare “coolant temperature in”, versus “coolant temperature out” in each circuit to evaluate the heat removal performance. A difference of 4 degrees F or larger is undesirable and indicates poor rate of heat removal.

Plastic variable measurement is independent from machine variables and can be repeated on any injection molding machine.

I hope this information will help on your next project.

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Plastic Design International was started in 1977 in the short-run prototype R&D business. PDI is now one of the most effective Plastic Injection Molding production companies on the East Coast and an expert Mold Making manufacturer. Please contact us with any questions at 860-632-2001.


View the original article here