Servicing, repair, rework of injection moulds. Ours or any other moulds.

All moulds have a lifespan. Decisions made at the start of a project will have significant impact on the life of a mould. When building a mould for you we use the very best materials and experience available to us at that time.

"The quality remains long after the price is forgotten" was once quoted by another English engineering company. In fact it was Mr Royce of Rolls Royce who made that famous quote....

At GMT we spend a lot of time educating our customers on how to drive future costs out of moulds. But at some point they will need to be serviced, repaired, changed, modified, updated, upgraded etc etc. When we design adn build a mould for you we engineer it to standards that limit down time and return to workshop.

 

If you have any type of mould either made by us or someone else then we will be happy to look at it and can quote on service, repair or upgrade. Mould making has to run hand in glove with the sales and marketing of your products. Often small changes are needed and of course we can complete that work for you.

Examples

  • Change in packaging laws require addition of symbols or markings. (Metal "off"). Easy for us to engrave any mould.
  • Creating of inserts to accommodate different sizes, wording, company logos.
  • Part refurbish of a mould to replace or repair worn parts. IE ejector pins.
  • Full refurbish of a mould to repair severe damage, minor damage, or overhaul.
  • Blanking plates or changes to the surface of the mould.
  • Minor or major modifications to changing client projects for your ongoing projects as a result of testing or feedback
  • etc

 

We are aware of the many issues that affect injection moulding and can work with you to correct all the common types of mould problems and defects.

Some examples of common issues that arise in injection moulding are listed below

 

Molding DefectsAlternative nameDescriptionsCauses
BlisterBlisteringRaised or layered zone on surface of the partTool or material is too hot, often caused by a lack of cooling around the tool or a faulty heater
Burn MarksAir Burn/ Gas BurnBlack or brown burnt areas on the part located at furthest points from gateTool lacks venting, injection speed is too high
Color StreaksLocalized change of colorMasterbatch isn't mixing properly, or the material has run out and it's starting to come through as natural only
DelaminationThin mica like layers formed in part wallContamination of the material e.g. PP mixed with ABS, very dangerous if the part is being used for a safety critical application as the material has very little strength when delaminated as the materials cannot bond
FlashBurrsExcess material in thin layer exceeding normal part geometryTool damage, too much injection speed/material injected, clamping force too low
Embedded contaminatesEmbedded ParticulatesForeign particle (burnt material or other) embedded in the partParticles on the tool surface, contaminated material or foreign debris in the barrel, or too much shear heat burning the material prior to injection
Flow marksDirectionally "off tone" wavy lines or patternsInjection speeds too slow (the plastic has cooled down too much during injection, injection speeds must be set as fast as you can get away with at all times)
JettingDeformed part by turbulent flow of materialPoor tool design, gate position or runner. Injection speed set too high.
Silver streaksCircular pattern around gate caused by hot gasMoisture in the material, usually when hygroscopic resins are dried improperly
Sink MarksLocalized depression (In thicker zones)Holding time/pressure too low, cooling time too low, with sprueless hot runners this can also be caused by the gate temperature being set too high
Short shotNon-Fill / Short moldPartial partLack of material, injection speed or pressure too low
Splay MarksSplash mark / Silver StreaksCircular pattern around gate caused by hot gasCaused by the material (plastic) being damped prior to injection
StringinessStringingString like remain from previous shot transfer in new shotNozzle temperature too high. Gate hasn't frozen off
VoidsEmpty space within part (Air pocket)Lack of holding pressure (holding pressure is used to pack out the part during the holding time). Also mold may be out of registration (when the two halves don't center properly and part walls are not the same thickness).
Weld lineKnit Line / Meld LineDiscolored line where two flow fronts meetMold/material temperatures set too low (the material is cold when they meet, so they don't bond)
WarpingTwistingDistorted partCooling is too short, material is too hot, lack of cooling around the tool, incorrect water temperatures (the parts bow inwards towards the cool side of the tool)

 

One of the major advantages they have over offshore mouldmakers lies in our engineering experience. What we can produce is far superior to most offshore mouldmakers

The truth is that customers who look simply at up-front mold costs are very short sighted and they're going to cost themselves a lot of money in the long run.

The real cost of a mold is determined by how long it lasts and how many parts it will make before it needs to be replaced, not by the up-front cost. The number of parts it will make is determined by the number of cavities and the cycle time of the mold.

GMT produce multi-cavity moulds and our engineers typically speed up mold cycle times. What we do here for customers, they generally can't get in other places, especially China, where most molds are single cavity, slow and frequently short lived. We spend a lot of time trying to educate our customers and potential customers about the true economics of moldmaking."

Fighting Back In spite of his company's engineering know-how, GMT still had to find a way to beat the low labour costs of their overseas competitors. "What we needed was a way to cut our production costs and speed up the moldmaking process,

"If you can get your costs within 20% to 30% of offshore costs, a lot of customers will stay with you. But to do that, we needed to automate as many of our processes as possible, and that's where we have invested our money heavily over the past two or three years."

"At any given time we may have ten to fifteen new molds on the floor,". "We purchased a flexible manufacturing system with 18 pallets that allows us to do a lot of production, virtually unmanned production." Seeing the precision and cost savings possible with the flexible syste,

says they realized they needed to automate other processes, too. "That meant robots," he says. "So what we did is spend a couple of million dollars in the last year and a half. We bought three 3R Workmaster robots and some new EDM equipment. We have one robot on our Global CMM. We have one between two sinker EDMs feeding them, and we have one feeding a wire and a hole popper. We're the only mold shop in Southern California with a robot hooked up to a wire and hole popper combination." has not yet automated its standalone mills, but sees that coming in the future.