A Guide for Critical Review of Injection Molding Quotes

Apples to apples, or apples to oranges?

It’s a common, frustrating scenario: You send out an RFQ to find the best fit for your project, but the quotes you receive present the information in different formats and provide varying levels of information. That makes it hard to conduct a true apples-to-apples comparison of suppliers before choosing the right one.

Why not simply select the lowest piece price? Selecting a plastic injection molding supplier that can provide you with the least expensive part will likely cost you more in the long run. As we explained in a previous article, an approach relying only on piece price can lead to problems with part quality, deliverability, and support. As your project launch gets underway, your well-intended sourcing decision may end up putting your supply chain at risk.

Key Variables of Injection Molding Quotes

Here are some tips to help you interpret and understand injection molding quotes – plus questions you should ask molders to get the information you need to make a well-informed decision.

Part Quantity

How many parts are being produced at one time? Is the supplier quoting release quantities to meet your demand, or does the quote assume a large run quantity that will need to be warehoused for several months? 

Multiple runs require additional setups and result in more cost being concentrated in smaller release quantities. For a single large run, the molder may be able to negotiate a better deal on a larger resin purchase and you may both benefit from economies of scale. When comparing quotes, are all suppliers following the same method for quoting release quantities? If not, it’s hard to make an apples-to-apples comparison of those suppliers.

Tooling Variables

Many variables can influence how a tool is designed and built. Each one will impact initial cost, quality, scrap rate, and the total cost over the life of the tool. 

Molders often make different assumptions and choices in tool design, so it’s important to understand those differences and their implications. If a quote comes in much lower than the others, it’s likely missing some important details that can add hidden costs and increase your risk over time. 

Offshore or Domestic

Both domestic and offshore toolmaker markets have suppliers on both bookends of quality. Choosing a molding supplier that offers the lowest cost tool will often lead to disappointment. It’s better to get both domestic and offshore tool production pricing options that include all costs, including tariffs and freight. International freight costs can sometimes be as expensive as the tooling itself, so ensure that your supplier is sharing those costs up-front!

Timing

Is the timing quoted by the molder based on a realistic or overly optimistic schedule? Is the timeline shown on the quote for the tool build alone, or for fully launching that tool into production? There are many complexities to launching a program that should be considered in a timeline. Assess whether a project timeline is realistic or risky. Will missed deadlines result in extra costs for expedited steps later?

Assessment

Does a quote come with up-front activities before the tool is produced, such as mold flow analysis and a manufacturability assessment? A molder should do a thorough check on the feasibility of a design to identify and address potential problems before the tool build. Without this step, the molder may encounter problems that require expensive and time-consuming changes to resolve when trialing your tool into production.

Pre-production

A complete quote will include all steps of the production part approval process (PPAP), including sampling, quality control, layouts, and validation. For molders that use robotic automation, the cost for new end-of-arm tooling should be included in the tooling quote or called out separately. Ensuring that all costs from PO to PPAP are included in a supplier’s quote will help you make a better sourcing decision and help you understand what your money is going towards.

Parts Per Cycle

A molder may quote a tool with a single cavity to produce a single part, or multiple cavities that produce two or more parts in a single molding cycle. A family tool can be built to mold multiple unique parts in a single cycle, but a mold flow study may be necessary to determine whether this is feasible and what the impact on part quality is likely to be. When comparing quotes, make sure suppliers are using the same assumptions for cavitation. This allows for a more accurate comparison of the quotes you receive.

Steel Grade

Different grades of steel impact a tool’s durability. Harder steels are best for tools that will be used to run many parts over a longer time, or when molding a material with an abrasive additive. Softer steel is fine for lower production volumes or less abrasive materials. The steel choice should be based on the resin being used and the total cost for the life of the tool.

A tool made of softer steel may not hold up to stressful demands over the life of a program. As a result, it will probably require expensive refurbishments and there will be wear that increases the risk of out-of-spec parts. However, an over-engineered tool for less demanding programs may add unnecessary costs that add no value.

Tool Features

Some features can be added to a tool to improve part quality and save money in the long run. Hot manifold systems will add cost to a tool but will reduce part price and create savings over time in the correct application. 

Some molders use a scientific injection molding process to improve part quality and processing. Sensors are added to the tool to monitor the manufacturing process during production, which ensures better quality, reduces scrap, and increases the level of support your supplier can offer. Having your supplier explain why they quoted a particular tool design features will help you understand the cost-benefit trade-off of those choices.

Runner Type

A molder will recommend a melt delivery runner system based on many factors. A cold runner option leaves a sprue attached to the molded part, but a hot runner does not. 

Cold runners are less expensive upfront but result in extra waste, a higher part price, the potential for cosmetic blemishes, and the need to remove remnants. 

Hot runners will add some cost to your tool but result in a better manufacturing process and savings over the life of a program, especially for high-volume projects.

Assembly and Packaging

Will the molder provide individual parts or assemble multiple parts before shipping? How will those parts be packaged to provide the best protection and the lowest shipping cost? Make sure all suppliers are quoting the deliverable you intended.

The New Berlin Plastics Difference

“To make our quotes very clear, they are all-inclusive and detailed so OEMs can use them to properly budget and plan their product launches,” explains Joseph Mechery, VP of Sales. “We provide a comprehensive description of all aspects of the project, along with timing, pricing, and options. There are never any hidden costs, so customers can write a single P.O. based on the quote we provide that will take them all the way to production.” 

An injection molder can have a major impact on a product launch, so sourcing the right molder is a critical task that requires careful consideration. 

Arm yourself with all the information you need to make the right choice by requiring complete quotes with all the steps and costs that go into that project. Once you have a clear understanding of how each molder balances costs and risk levels, you’ll have the confidence to make an informed sourcing decision.