Mould Inserts setup, maintenance and daily checks
Mould Inserts is a replaceable steel component that forms part of a mould cavity. It is used for moulds where a wear area, a core or a detail needs to be replaced or machined separately. This entry explains what it is, what the numbers on a data sheet mean, and what to put on a drawing.
It is written from the point of view of the buyer and the drawing office: the values that are realistic in production, the ones that cost money, and the way the result is verified. Where an industry sets the requirement, food processing is used as the example: surfaces that clean down between production runs.
Setup
- Establish the datum on the part or the fixture and indicate it, rather than assuming it.
- Set the tools and record the offsets; a tool length set by eye is the commonest source of a scrapped first part.
- Run a first part, measure it, and adjust from the measurement.
Daily checks
- Coolant concentration and flow, because a dry cut changes both the tool life and the size.
- Chip clearance in the fixture, because a chip under the part moves it.
- Verification: CMM for the form, and a fit check in the bolster, repeated at the start of a run and after any adjustment.
Wear and consumables
Tools, filters and coolant are consumables, not overheads. The detail and the finishing requirement, and the cost of replacing them early is far below the cost of a scrap part.
| Specification | Typical value |
|---|---|
| Material | H13, or a higher alloy for abrasive plastic |
| Hardness | 48 to 52 HRC typical |
| Typical tolerance | ±0.01 mm on the shut off faces |
| Surface finish | to the mould texture specification, or polished |
| Fitting | interchangeable, with a locating method |
| Cooling | drilled channels or a baffle |
Applications
Mould Inserts is used for moulds where a wear area, a core or a detail needs to be replaced or machined separately, and in practice it appears most often in injection moulds, die casting tools, blow moulds, prototype tooling.
How it fits into a machining route
Mould Inserts is produced by whichever route reaches it most reliably, and it is usually the reason the rest of the part is dimensioned the way it is. Datums are chosen so that this feature is measured from what it actually has to be square or concentric with.The route is fixed before the first part is cut, and it is the route rather than the individual setting that holds the result: the detail and the finishing requirement. Where a drawing calls for something the route cannot hold economically, that is raised at quotation rather than after the parts are made.
Standards, documentation and what is issued
The documentation requirement is in-house approval with dimensional reports. Material is supplied against a certificate where the application calls for it, inspection results are recorded with the job, and the records are kept so that a repeat order can be compared with the first instead of being measured from scratch.
CMM for the form, and a fit check in the bolster is the verification step. Where a customer format or a standard report is required, it is agreed before the batch starts, because a report written after the event is a report nobody can use.
Frequently asked questions
What tolerance should be specified for Mould Inserts?
±0.01 mm is realistic in production. Tightening it beyond the functional requirement increases cost without improving the part.
Which material is usually used?
H13 tool steel is the usual choice, supplied against in-house approval with dimensional reports.
How is the result verified?
CMM for the form, and a fit check in the bolster, with the results recorded so a repeat order can be compared with the first.
What is the most common mistake?
A shut off face that is not square, which flashes.
How long does it take and what does it cost?
A realistic cycle is 4 to 20 hours per insert, and the cost driver is the detail and the finishing requirement.
Related capability
If you are specifying Mould Inserts on a drawing and want a second opinion on the route, send the model and the quantity. The first response is a manufacturability review with the likely risk points and a quotation, so the decision can be made on facts rather than on a price alone.
Machining, inspection and documentation are handled in one place, which is why the dimensional report and the material certificate arrive with the parts rather than after them.
Related entries
These entries sit next to Mould Inserts in the encyclopedia: Hydraulic Manifolds, Heat Sinks, Geometric Dimensioning and Tolerancing. Reading them together gives a fuller picture of how the process, the material and the measurement affect each other.
