The price of making a perfect approval sample of drinking glasses using the machine blown process is expensive. Lets go over some of the costs listed by our Buying Office in Shanghai….
Initially there is a high cost of making a metal mould into which the molten glass is poured. If the client does not have a mould to supply to the factory, the factory will have to create a mould following the design specifications of the client. Many factories that manufacture glasses using the machine blown process outsource this and contract it out to a professional mould maker.
If the factory doesn’t have in-house capabilities for designing a mould then the costs can further increase. There are typically defects in most moulds, meaning that factory needs to amend the mould following the first samples.
Another important factor for high costs of making a glass sample is the complicated production process.
Once the mould is ready the machines can start to run the production of sample glass products. The machine needs to operate for a full day or more before starting to produce flawless glasses. Usually the first and second days most of the production is destroyed and recycled because of defaults in the glasses (see previous blog for list of possible defaults).
It takes some time depending on the complexity of the mould before obtaining perfect glass products that can be shipped to clients as Production samples. Each piece is run through an automatic inspection machine which verifies if the sample follows the exact requirements made by the client. If there is just the slightest default the sample will be destroyed and more will need to be produced.
Every time the automatic inspection machine detects a default it relays the information to the production machinery in order for changes to be made on all the variables.
Once automatic inspection has passed, the factory will perform a manual inspection as well.
Since production lines are up and running from a few hours up to a full day or more the cost of making a sample can be very expensive. The sample cost would need to cover the cost of running the machinery and making all the required automatic and manual inspections.
Factories can provide rough samples at little cost apart from mould charge, but a lack in the clarity of the glass, variations in thickness of the glass, and the possibility of small cracks and defects are to be expected if you are doing a limited production run.
The more complex the mould the more expensive the sample – any mould that is customized such as requiring a thinner wall size, or engraved shapes will be expensive to sample.