It’s hard to break old habits—like using metal parts and metal
products. However, there are three good reasons for changing from metal
to plastic:
- Lower manufacturing cost
- Lighter weight
- Zero corrosion
What many manufacturers don’t know is that—when done properly—plastic
parts can be injection-molded with the same tight tolerances and
perform just as well (or even better) than their metal counterparts.
Careful design and planning, selection of appropriate materials, and use of scientific injection molding
principles will control the main factors that affect precision,
accuracy, and tight tolerances—these include material preparation, melt
flow index, machine processing parameters, and most importantly, using
sophisticated sensor technology to track what is happening inside the
mold in real time. Making these kinds of high-performance plastic parts
therefore also requires a robust quality system that can monitor every
step of the injection-molding process.
When injection-molding vendors fail to meet tolerances consistently
with plastic parts, this creates additional machining costs, quality
costs to sort or even re-call parts, and possibly even litigation.
(Source: Plastic Overmolding by Kaysun)
It only takes one bad experience with plastic parts to drive a
company back to metal. But, with an experienced
metal-to-plastic-conversion injection molder, there are some big
advantages in going with plastic, such as:
Lower cost to produce
No secondary process to prevent oxidation
May be able to eliminate some assembly
Plastic is generally less expensive than metal
May be able to eliminate costly machining operations
Lighter weight means lower shipping charges
No painting needed, molded in color/graphics
Lighter weight
Less fatigue on a person if it is carried
Might make a product go faster
No secondary process to prevent oxidation
May be able to eliminate some assembly
Plastic is generally less expensive than metal
May be able to eliminate costly machining operations
Lighter weight means lower shipping charges
No painting needed, molded in color/graphics
Lighter weight
Less fatigue on a person if it is carried
Might make a product go faster
The key is to successful metal-to-plastic conversion is understanding
the limitations of the process, materials, and tools are before
committing to the project. Every part or product is not necessarily a
good fit for metal-to-plastic conversion: important factors that must be
carefully considered are the expected tolerances, materials, specific
part design/configuration, and initial mold flow/analysis.