Engineers specifying Solvay KetaSpire PEEK KT-820 for semiconductor and electronics hardware ask the same questions over and over. Here are direct answers, based on the grade’s actual behaviour on the shop floor and in the fab.
1. What exactly is KT-820, and how is it different from KT-880?
KT-820 is Solvay’s high-viscosity (high molecular weight) polyetheretherketone grade. KT-880 is the low-viscosity counterpart. The difference is flow, and it drives everything downstream: KT-820 delivers better toughness, fatigue resistance and environmental stress crack resistance, while KT-880 fills thin walls and long flow lengths more easily. Rule of thumb: structural parts, thick sections and extruded stock shapes go to KT-820; high-cavitation connectors and thin-wall housings go to KT-880. In viscosity class, KT-820 sits alongside Victrex 450-series and KT-880 alongside 150-series.
2. What temperature can it actually take continuously?
Glass transition is roughly 150 °C and melting point roughly 340 °C. Practical continuous service is 240–250 °C, with short excursions higher. Be careful reading HDT: unfilled KT-820 shows around 160 °C at 1.8 MPa, but a 30% glass-filled version jumps above 300 °C because the crystalline structure carries load once reinforced. Do not use the unfilled HDT number to reject the material for a hot application — check the filled grade instead.
3. Why is it specified so often for semiconductor wet-process parts?
Three reasons: chemical resistance to hot SC-1/SC-2 baths, dilute HF, ozonated DI water and IPA; very low ionic extractables and particle shedding; and dimensional stability under thermal cycling. Typical parts are wafer carriers, CMP retaining rings, test and burn-in sockets, vacuum chuck components, and plasma chamber insulators. The limit worth knowing: concentrated sulfuric acid and strong oxidisers at elevated temperature will attack PEEK. Confirm the specific chemistry and temperature before committing.
4. Do machined parts need annealing?
Yes — and skipping it is the most common failure we see. Parts machined from extruded or compression-moulded stock carry residual stress that releases later as warp, dimensional drift, or stress cracking on chemical exposure. Use a stepped anneal ramping to roughly 200 °C with slow cooling. The correct sequence is rough machine → anneal → finish machine, not finish-then-anneal.
5. What moulding parameters should I start with?
Dry the resin at 150 °C for at least three hours to below 0.02% moisture. Melt temperature typically 360–390 °C. Mould temperature is the parameter people get wrong: run 175–205 °C. A cold mould produces an amorphous skin that looks fine but has markedly poorer chemical resistance and will craze in service. If your tool cannot reach that range, expect field failures rather than moulding defects.
6. Glass-filled or carbon-filled?
GF30 gives stiffness and creep resistance at lower cost, but it is abrasive to tooling and a poor choice for sliding contact against soft counterfaces. CF30 gives higher stiffness, better thermal conductivity and lower CTE — useful where you are fighting thermal expansion mismatch against silicon or ceramic. One caution: standard carbon-filled PEEK is not automatically static-dissipative. If you need a defined surface resistivity window, specify a purpose-made ESD grade and ask for measured data, not a datasheet inference.
7. What about outgassing and cleanliness qualification?
Unfilled PEEK generally meets ASTM E595 low-outgassing criteria, which is why it appears in vacuum and space hardware. But pigments, fillers and mould release can change the result, so qualify the exact grade and colour you will buy, not the polymer family. For fab use, request lot-level COA plus extractables and trace metals data.
8. Any procurement notes?
Resin pellets and semi-finished stock shapes run on different supply chains and different lead times — stock shapes are usually converted by licensed distributors, so allow extra weeks. Lock the grade code, colour and lot traceability in the purchase order. Substituting a nominally equivalent PEEK from another supplier without re-qualifying anneal and mould parameters is where most cost-saving attempts go wrong.
Always verify final values against the current supplier datasheet and your own qualification testing before release to production.
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