Custom Tips for Injection Molding

When working with metal, whether its cutting a tool or machining a final part, some features are too small to produce using traditional machining methods. For these applications, a process called electrical discharge machining (EDM) is used. EDM is also referred to as spark machining, spark eroding, burning, die sinking or wire erosion.

What is EDM?

Electrical discharge machining (EDM) is a metal working process in which controlled sparking is used to erode away a work piece. The EDM system consists of an electrode and the part (work piece). Material is removed from the work piece by a series of rapidly recurring current discharges between the two electrodes, separated by a dielectric liquid and subject to an electric voltage. It is one of the most accurate manufacturing processes available for creating complex or simple shapes and geometries within parts and assemblies.

When is EDM used?

EDM is primarily used for hard metals or those that would be very difficult to machine with traditional techniques. EDM typically works with materials that are electrically conductive and can cut intricate contours or cavities in pre-hardened steel without the need for heat treatment to soften and re-harden them. This process is most widely used by the mold making tool and die industries, but is becoming a more common method of producing prototype and production parts where quantities are relatively low. EDM manufacturing is a very desirable manufacturing process when low counts or high accuracy is required.

Some of the advantages of EDM include machining of:

• Complex shapes that would otherwise be difficult to produce with conventional cutting tools.
• Extremely hard material to very close tolerances.
• Very small work pieces where conventional cutting tools may damage the part from excess cutting tool pressure.
• There is no direct contact between tool and work piece. Therefore delicate sections and weak materials can be machined without any distortion.

Some of the disadvantages of EDM include:

• The slow rate of material removal.
• The additional time and cost used for creating electrodes for ram/sinker EDM.
• Reproducing sharp corners on the work piece is difficult due to electrode wear.
• Specific power consumption is very high.

Have questions about EDM and how it can help you?  Call your Sales Manager at 770-901-3200 to discuss your project today!

The Game Gripper is a hand-held instrument used to convert the Motorola Droid keyboard into one of the best performing gaming handsets on the market. The device fits over the phone and comes with custom buttons that align to the keyboard perfectly, dramatically enhancing the gaming experience while using the Droid handset.

Hyrum Fairbanks, the device inventor, spotted a need in the market for the device when he found the keyboard very clumsy and tough to use for gaming. “The Droid has some of the best games available on the market, but the keyboard was a limiting factor in how much the user enjoyed playing the games. My product made the phone great for gaming, I just needed a company to help me make them economically. Quickparts helped me make the design and material changes I needed to bring the costs down and bring it to market.”

In addition to the Motorola Droid, Game Gripper is in the process of releasing several other models that will allow users of other popular phones on the market to enjoy similar gaming benefits.

Injection molding is the manufacturing process that is responsible for producing most of the plastic parts that we come in contact with each day.  The injection molding process is capable of producing a wide range of    designs; however, it is a long one that does not allow for easy changes.  It is for this reason that Quickparts has created a new injection molding concept called Proto-duction tooling.

Prototype in Cavity-1, Production in Cavity-2, 3, 4 when ready

Quickparts has perfected the process of building “Proto-duction” tooling, also known as ‘Prototype-to-Production” tooling. This type of tooling is production steel multi-cavity tooling, with the 1st cavity being the prototype tool. When the 1st cavity is constructed, sampled, adjusted, and approved, then the remaining cavities are built to match the prototype cavity. The result is a production multi-cavity steel injection mold tool, in half the time of the traditional 2-step process of building a stand-alone prototype tool, then a multi-cavity production tool.

Construction timelines have been reduced, since the typical ‘prototype’ tooling phase tightly integrates with the construction of the production tool. Overall tooling cost is reduced, since stand-alone prototype tooling is avoided. Financial risk is mitigated, since you don’t order the construction of the remaining production cavities until the prototype cavity is approved.

Proto-duction Tooling is a cost effective way to produce prototype and production tooling. There are no geometry limits, no volume limits and no manufacturing limits on your part. Any commercially available material can be used in the production of the part and any surface finish can be applied.

Want to learn more about Proto-duction tooling?  Visit Quickparts to find out how proto-duction can work for you at http://www.quickparts.com/ToolingProduction/ProductionInjection.aspx.

So what is Design for Manufacturing? Why do I care? 

These are a couple questions we hear in the development phase of a new product.  The brief description according to wikipedia.com is that DFM is the general engineering art of designing products in such a way that they are easy to manufacture. The basic idea exists in almost all engineering disciplines, but of course the details differ widely depending on the manufacturing technology.

DFM is intended to prevent:

• Product designs that simplify assembly operations but require more complex and expensive components
• Designs that simplify component manufacture while complicating the manufacture process
• Designs that are simple and inexpensive but are difficult or expensive to service and support

I think that is a good overview of the general concept of what DFM is.  So the next question is “why is it a problem?”

There are a number of possible answers for this question.  First possible answer is that the manufacturing techologies are continuously changing so it is difficult to keep up with the new technologies available.  This could be true…I am not sold though.  The next answer could be that engineers are not trained properly coming out of college.  This is a possible answer but it seems like it blames the problem on someone else.  Last, the answer could be that engineering is no longer performed at the same facility as manufacturing….bingo! 

With manufacturing moving offshore to locations far away from engineering, the collaboration that existed in the past between design engineering and manufacturing no longer happens.  Designs are created and then passed to manufacturing to make parts.  Sounds great and very efficient…just not as flawless in practice.  How does an engineer learn about the hidden “gotcha’s” of injection molding? Well, unfortunately, they don’t.  Not until they design a part and have it manufactured do they see problems.

With that said, there are now services out there to help with the manufacturing process during the product development phase.  We are Quickparts provide a DFM of every part we review for injection molding.  We saw the void created in the industry and want to provide a free service that helps both our customers and us during the manufacturing process.  We have seen this as a huge success for customer wanting to proceed to injection molding.  This has helped product development companies reduce cost, lead time and ultimately FRUSTRATION. 

To learn more about the service or see an example, give us a call or check Quickparts out at http://www.quickparts.com/ToolingProduction.aspx.

Here is an example of a DFM report: http://www.quickparts.com/UserFiles/File/Design_For_Manufacturing_analysis_report.pdf

Quickparts.com (www.quickparts.com) has launched a new video series starring Johnny Quickparts. He will be sharing his adventures in product development. Johnny is the star engineer in Better Be Running! Tools to Drive Design Success, an “almost” best selling book on product development and manufacturing.

A video series with a common character is a very unique approach to marketing in manufacturing. Most manufacturing information is very dull and boring. The video information that is available is typically shots of a machine doing something….great for 10 seconds, then dull after that….some may know the feeling.

There will be another 15 episodes this year and then the execs at NBC/CBS/ABC will decide if they cancel it (if they too busy, then we will decide the future).

Please check out the video and let us know what you think.

http://www.youtube.com/user/JohnnyQuickparts

Have you ever been frustrated with those critical features that other quick turn injection molding companies told you were too small to produce? Quickparts utilizes the EDM process to produce the small features and sharp corners desired for many injection molded parts.

What is EDM?

Electrical Discharge Machining (EDM) is a machining method primarily used for hard metals or those features that would be impossible to machine with traditional techniques. EDM is especially well-suited for cutting intricate contours or delicate cavities that would be difficult to produce with a grinder, end mill, or other cutting tools. EDM functions by removing very small amounts of metal by producing a rapid series of electrical discharges. These electrical discharges are passed between an electrode and the metal being machined, and create a set of successively deeper craters until the final shape is produced.

To learn more about the services offered at Quickparts, visit www.quickparts.com or call us at 770-901-3200.

Ever wonder what the best gate type is for the design you are working on?  Yes, many other has wondered the same thing.  Well, there is a great site out there to help explain what the different gate types are.  It covers injection molding gate types from simple sprue gate all the way to a valve gate using a hot manifold system. 

Also, the information includes which gates need to be manually trimmed off the molded part and which gates are automatically trimmed during the molding process.  All this information can be found at http://www.dsm.com/en_US/html/dep/gatetype.htm. 

Gate types are just one of a number of variables that can dramatically impact the cost and the quality of the part.  If you are looking to discuss more of the manufacturability of the part, you can talk to the team at Quickparts about receiving a Design for Manufacturing review…they are free!

Contact us at www.quickparts.com or call us at 770-901-3200!

One of the ways that companies have been able to reduce lead times for new injection molds is to use quick change mold systems.  This typically means that there is a common mold frame that is stationary in the molding machine and the only part being constructed is the core and cavity inserts.  This system creates several advantages for creating new injection molds.

1. Faster Delivery – The only part being constructed is the core and cavity inserts and not a complete mold base.  This allows for less machining and the material to build the core and cavity inserts is typically kept on hand.  This saves days in waiting for mold material to arrive.

2. Lower Tooling Costs – Since the only features being constructed are the core and cavity inserts, there is less machining costs and material costs.  DME states that the cost savings can be as much as 66%.  I don’t think it is quite that much but it can be significant.

3. Easier Engineering Changes – Many times, quick change molds are created for a single cavity.  Also, they do not have an elaborate mold base structure and this allows for less complicated engineering changes.  Especially if the parts are straight pull.

Now there are definitely some drawbacks to quick change mold unit systems.  High cavitation molds won’t really work and if the part requires a hot manifold systems to allow for injection of plastic, the unit die will not work.  These are just a few drawbacks but overall, for low volume injection molding, quick change units meet the requirements.

To learn more about the options available for injection molding, please give us a call at 770-901-3200 or check us out at www.quickparts.com.

Draft and wall thickness are two of the most critical and overlooked fundamentals when manufacturing and designing for injection molding.

Draft

Draft is a design feature that involves tapering the side walls of a part to allow it to be released from the mold when the mold opens. Drafting walls in the direction of the mold helps to prevent sticking and dragging as the part ejects.
The recommended draft angle for parts is 0.5 to 1 full degree of draft on all surfaces. If your part includes textured walls, you will need to increase the amount of draft to ensure clean ejection. We suggest that 1.5 – 2 degrees of draft be used per 0.001″ of texture depth. This rule is for sidewalls of the tool that will shrink away from the cavity. Areas in the part that will shrink toward the core of the tool will require more draft. The amount of draft needed for these walls will vary based on part design.

Wall Thickness

Wall thickness is another critical component of design that can affect the success of your injection molded part. If the walls of your part are too thin, you may have cracking or warping of your part. The type of plastic resin that you choose will help determine the wall thickness needed. Each resin has a unique blend of properties that include varying amounts of plasticizers, stabilizers, fillers, and other additives. These properties determine each resin’s flow and strength values. Refer to the chart to the to see the recommended wall thicknesses of some common resins.

If you have further questions or would like to receive a quote please call us at 770-901-3200 or visit www.quickparts.com.

Have you ever wondered how a screw driver is manufactured?
The answer is overmolding. What is it? The overmolding process involves the use of two separate materials to form one cohesive component. There are two types of overmolding: insert and “two-shot”. Insert overmolding, the more popular process, is an injection molding process where one material (usually elastomeric) is molded “over” a secondary “substrate” material (usually a rigid plastic or object).
Overmolding can add immeasurable value to product design by enhancing the end users experience in terms of comfort, ergonomics, and ease of use. In order to achieve this level of manufacturing there are two important concepts that must be understood for success to take place:
1) Know your materials
The materials used need to be compatible so that your designs attain a high level of molecular adhesion. Know what the melt temperature is of your substrate and overmold. If the melt temperature is lower on your substrate than your overmold material, then you are in for a big problem! Also, if you are using color, make sure your color concentrate is compatible with your other materials and won’t degrade their properties. Using the right materials could make or break your designs.
2) Understand your designs
When designing, you need to consider how much or how little you want your substrate and overmold to stick. Don’t count on the material alone to create the adhesion that you want. To ensure that the components “mesh” well with one another use mechanical interlocks such as these:

Knowing the proper rules for overmolding can yield a very successful and aesthetically pleasing product. Feel free to contact at www.quickparts.com to learn more about overmolding and how Quickparts can help!