Role of Design in Manufacturing through Injection Molding: A Detailed Guide

Role of Design in Manufacturing through Injection Molding A Detailed Guide

Have you ever wondered how plastic parts, and other products come to life? Or are you interested in how geometric parts turn into reality? If yes, the short answer is design in manufacturing or DfM through injection molding.

One of the reasons why injection molding is a preferred manufacturing technique is because of cost-efficiency and being almost fool proof.

The stage where everything must be perfected happens in the design phase. As such, you would expect that design in manufacturing or DfM carries the most important role in injection molding.

In this post, we shall look at not just the importance of DfM in injection molding but also the factors to consider during the process. Knowing what to do and what not to do during DfM gives you miles ahead in injection molding for manufacturing so read on.

Why is DfM Important in Injection Molding?

Time and again, manufacturers would tell you that everything starts with design. It determines the material to be used, the type of machine to go for, and the expected product to come out. In this section, we square the significance of DfM in injection molding.

1. Feasible Manufacturing Process:

Feasible Manufacturing Process

Sure, you have the design in your head already. But is it workable? Given all the specific processes to come up with it, is the design feasible? This is where DfM becomes very significant in the manufacturing process.

Note that in the DfM stage, you can already insert modifications to make the project workable. As such, you would not need to reach the actual production phase to determine if some parts or specifications need to be changed. Now, how is this done?

For example, through 3D printing of prototypes, you would see if there are parts that are too bulky or not collapsible. If you find such a barrier in the prototype, then you can address the design to make it feasible.

2. Foolproof Parts:

Injection molding is all for parts functionality. And it is always a hassle if the parts start cracking or become dysfunctional right after production. Fortunately, this incident could be avoided with DfM.

With the right design, and the level of modification, testing, and validation that comes with it, potential faulty parts and added costs in production may no longer be a problem.

Remember that with DfM, aided with applications such as 3D printing and CNC machining, you can have a view of how the product would be without actually producing it first.

3. Identifying Manufacturing Complexities:

Identifying Manufacturing Complexities

Just as in the uncertainty of knowing if the injection molding parts will work without DfM, complexities in manufacturing are also more or less unknown. Again, with the help of DfM, producers can identify design obstructions before production.

How does this work, you may ask. With thorough design evaluation, manufacturing complexities can be upended with the use of draft angles or inserting undercuts.

As a result, manufacturers could better tweak the design, if need be, in the right degree, shape, and angle. Simpler designs may also be available at this point, lessening the overall cost of the production.

Note that this list is not exclusiveAs a matter of fact, you can find injection molding as highly applicable in almost any field. As such, there are other significant contributions of the process that did not make the list. If you want to know more, you can check out Kemal Manufacturing.

What Factors Should be Considered During DfM in Injection Molding?

You might think that DfM is an easy process. Well, you must rethink that notion. This section shall familiarize you with the most important considerations to bear in mind during DfM in injection molding.

1. Selection of Materials:

Selection of Materials

It is true that injection molding is applicable to a wide range of materials especially plastics. However, not all materials are suitable for all projects.

Hence, in selecting which material to use, you have to take note of the following:

How Expensive Are They?:

Producers could easily inventory the materials needed for your project. But designers in DfM have a helpful perspective. Materials cost involves not only the upfront price of the material. Designers include in the costing, labor costs, maintenance, machining expense, and finishing.

Are They Easy to Assemble?:

Note that not all plastics are made the same. Some are softer, but are delicate to assemble. Some are harder, which makes them more complex to assemble.

As is the case, you need to know the properties of the materials that you use too. Plastic Components reveal that knowing the threshold of plastics during assembly helps especially during the bonding, welding, or fastening of large products.

What is the Materials’ Shrinkage Rate?:

The cooling off part after injection molding is probably the most crucial phase. Bad quality cooling will lead to warping and shrinkage. 

The shrinkage rate of plastic materials in injection molding is attributable to various factors. Spectrum Plastics identifies some of these factors as pressure, melt flow, the type of plastic used, and more.

Shrinkage rate is important in materials selection because it determines the extent of geometry you can incorporate in the design.

2. Draft:

The draft angle is an important component of DfM. Essentially, the right draft angle ensures that the molded object is easily removed or ejected after the molding process.

Because of the importance of draft angles, manufacturers give considerable time in incorporating them in the final design of products. Having enough clearance room for the molded object to be ejected makes sure that the final product is free from manufacturing dents and other impurities.

Crescent would suggest that going for a parallel angled draft is the best choice for injection molding. 

3. Wall Thickness:

Wall Thickness

Uneven fill in the mold leads to uneven shaped products. The culprit behind this is usually inconsistent wall thickness. In DfM, uniform wall thickness is prescribed to avoid major defects in the final product.

Jaycon Systems breaks down the consequences of uneven wall thickness in the DfM process. One, the molten plastic will concentrate in the areas with thicker walls. Hence, uneven filling would result to deformed products.

More so, thicker areas tend to cool down faster. Hence, another case of morphed and deformed shapes. You would not want this of course. So, you better make sure that you incorporate uniform wall thickness in your mold design.

4. Gate Location:

As the term implies, gates regulate mold flow. Hence, you would know that the material ends up in the right cavities because you have well-positioned gates.

In DfM, manufacturers involve trial and error when they position the gates in strategic locations. The gates are further inspected to see if the locations either obstruct or make the flow too fast. For this part, Natech Plastics suggest that the gates should not be too engorged so that the runner can be easily detached from the molded part. 

5. Consider Ribs:

Albeit the scare of deformation and other impurities, some manufacturers still resort to thickened walls. It is a misnomer that thicker walls would reinforce material strength.

DfM experts would tell you that incorporating ribs instead of thickening the walls is a better option. According to one company, the best rib range is 50-70%, relative to the wall thickness.

The inclusion of ribs in DfM paves way for strengthened parts without fear of crack or deformation in the final product.

6. Infuse More Radii:

Do not fear adding more radius to your mold. This especially holds true for the corners and edges. DfM rule of thumb tells us that the steeper the edges and corners, the more pressure is built at the junctions.You would not want this to happen because it means breakage.

Thus, as an intervention, infuse more radius in your edges and corners. Aside from releasing pressure in the junctions, hence, stronger parts, it also allows better mold flow.

7. Make Use of Undercuts:

If you are working on parts using larger contraptions, the use of undercuts would be good. The only limitation in undercuts is that they add to the production cost and they may obstruct the ejection of the molded part.

Aside from the fact that you should familiarize yourself with the factors, you should also consider some of the suggestions that we have laid down in this section for you. It will save you the expense and changes in the design. 

Benefits of DfM Analysis in Plastic Parts Production

Benefits of DfM Analysis in Plastic Parts Production

DfM analysis includes not just the creative aspect of design. More than ever, it involves strategic positioning of parts and features, among others. The following are some of the benefits of DfM analysis in the production of your plastic parts.

1. Lead Time is Faster:

DfM analysis ensures that all the parts of the product are functioning and of high aesthetic value. As such, extended hours of designing and modifying is significantly shortened. Thus, from design to production, you get a faster lead time compared to non-DfM production.

2. Faster Marketization:

Connected with faster lead time is faster marketization. According to Basilius, from design to production to marketing, DfM analysis hastened marketization to 70-93% faster than traditional production. From this figure alone, you can already surmise that faster lead time leads to faster marketization. Consequently, faster marketization leads to greater profits.

3. Lesser Production Cost:

3. Lesser Production Cost

Imagine having to produce fully functioning, guaranteed profitable parts with low-cost manufacturing. That is what injection molding has been delivering to manufacturers for the longest time.

With DfM analysis for instance, you are ensured that all that is produced as end-products have been thoroughly tested. And since you no longer need consumables, fasteners, and lots of trial and error in design, huge production costs are also reduced.

4. Quality Plastic Parts:

Quality Plastic Parts

Of course, the purpose of production is to ensure profit from fully functioning parts. Since DfM does the work of making feasible designs of products that are aesthetically and functionally topnotch through validation and testing, you get only quality plastic parts.

5. Low Waste Production:

Without DfM, you are looking at high production waste because of lots of trial and error starting from the design phase. Further, traditional injection molding includes the use of adhesives, fasteners, and consumables. These are all items of wastage in the assembly phase.

With DfM analysis, all these wastes are eliminated. Aside from the fact that you might not even need the assembly phase anymore, the precision that it gives at the onset allows you to focus on accurate production only.

See? From this list alone, you already have a backdrop of the good things that DfM can do for a stable and profitable production. If you want actual visuals as to how DfM benefits production, check out reputable injection molding companies like Kemal Manufacturing.

Why You Should Allow Kemal to Handle Your Plastic Parts DfM

Why You Should Allow Kemal to Handle Your Plastic Parts DfM

With the prevalence of injection molding in production, it is no wonder that a lot of manufacturing companies are switching to offering injection molding products and services. The market is competitive but you would want one which has been around for years, doing innovative jobs just like injection molding.

If you are looking for a reputable company which can handle your plastic parts through DfM, you can check out Kemal Manufacturing.

They have been around for more than two decades, offering comprehensive services and topnotch products using injection molding. Incorporated in their production is DfM analysis for better, more conclusive testing and production of functional parts.

What is the Principle of DfM Analysis?

DfM Analysis was introduced in the early 2000s at the dawn of innovative production techniques. This includes the introduction of 3D printing and CNC machining, among others.

Hence, the principle of DfM analysis is premised on the process of reduced production costs, improved manufacturing, and speedier marketization.

Where is DfM Analysis Used?

Aside from the injection molding industry, DfM has a virtually endless application. Electrical engineers and the electronics industry use DfM in testing circuit boards. DfM is also used in business planning, especially in cost-benefit analysis of investment plans and products to be manufactured.

What is a DfM Prototype?

A DfM prototype is made either from a CAD render, a CNC machined blueprint or a 3D printed wearable and usable test product. A DfM prototype is used in testing and validation. It allows engineers and designers to modify the design and make the product more feasible and usable.


The key takeaway of this post is that design for manufacturing or DfM upends injection molding through many ways. As simple as it may sound, DfM is not just insight based. It relies on testing, validating, and turning ideas into real products.

Some of the best advantages of DfM in injection molding is product feasibility, reduced lead time, costs, and wastage. In turn, there is faster marketization, and higher profits.

To make sure that these benefits are achieved, some factors and considerations must be put in mind. Some of these are draft angle factors, wall thickness, gate location, and other strategies in production.

Overall, DfM in injection molding creates better production opportunities for manufacturers. Aside from it being geared to high profits, DfM also ensures functionality and high product value.

Hence, if you want to know more about how DfM works, how it works, and how you can improve your own DfM steps, check out reputable sites, and companies like Kemal.


Rosti Group AB (2023). Plastic Injection Molding for Critical Parts. Retrieved from on June, 2023.

Rapid Direct (2021). Why You Need Design for Manufacturing in Injection Molding. Retrieved from on June 2023.

Jaycon Systems (2022). The Importance of Design for Manufacturing and Key Dynamics Involved. Retrieved from in June 2023.

Spectrum Plastics Thought Leadership (2023). The Importance of Design for Manufacturing. Retrieved from on June 2023.

Crescent Industries (2021). OEM’s Guide to Design for Manufacturability in Plastic Injection Molding. Retrieved from in June 2023.

Natech Plastics (2023). Why Design for Manufacture? Retrieved from on June 2023.

Basilius (2023). Designing for Injection Molding. Retrieved from on June 2023.

Put your parts into production today

Content in this article

Request A Quote

*We respect your confidentiality and all information are protected.