RFQ Checklist

The 3D model sets the steel; the 2D print sets what gets measured. A quote built from a model without a print has to guess which dimensions are critical, and a model that does not match the print revision causes rework after steel is cut.

• 3D solid model in STEP (.stp or .step) or IGES (.igs). TK designs molds in Siemens NX, so native NX files also open directly. Send solids, not STL or other mesh files.
• 2D print as PDF with critical dimensions, tolerances, datums and GD&T, at the same revision as the model.
• Surface finish and texture: SPI polish grade (for example SPI A2) or texture number for each cosmetic surface, and which surfaces are cosmetic.
• Gate and ejector limits: where gate vestige, ejector marks and the parting line may and may not go.
• Draft and undercuts: confirm draft is in the model, and flag any undercut the part must keep (slides, lifters and unscrewing cores add cost).
• Part family: if several parts run together or in a family mold, send all of them with the quantity of each.

Tip: mark the five or six dimensions that make the part work. Those become the critical dimensions TK measures at every trial, and they drive steel safe planning in the cavity.

Volume decides two things on the quote: how many cavities the mold needs, and how long it has to last. Mold life is counted in cycles, and the SPI mold classes are the common way to state it. Lifetime cycles are annual volume times program years, divided by the number of cavities.

• Annual volume for each part, plus the first year ramp if it differs.
• Program life in years, so lifetime cycles and the mold class can be set.
• Target cavitation, or ask TK to propose it from your volume and cycle time. TK builds from 1 to 256 cavities, including stack molds.
• Target cycle time or required output per hour, if you have one.
• Mold class or steel requirement, if your company has a tooling standard.

Plastic shrinks as it cools in the mold, and the cavity is cut oversize by that amount. Shrink differs by resin family, by grade and by flow direction in filled grades, so the exact grade is needed before steel is sized. A mold cut for a PC grade will make undersize parts if it is later run in PP.

• Resin maker and grade, not just the family: two PP grades can shrink very differently.
• Colorant or masterbatch and its letdown ratio; some pigments change shrink and warp.
• Filler and reinforcement: glass or mineral content. Glass fills shrink less along the flow than across it and wear the steel faster.
• Regrind limit, for example 0% for medical parts.
• Approved alternates: if the grade may change later, name the alternates now so the steel can be sized for both.
• Data sheet for the grade, with the maker’s shrink values.

An export mold has to hang in your press the day it arrives. TK designs the mold around the press it will run in, so the press spec sheet belongs in the RFQ, not in an email after the mold is designed.

• Press make, model and clamp tonnage for each press the mold may run in.
• Tie bar clearance, horizontal and vertical, and whether you load from the top or the side.
• Platen bolt hole pattern and clamping: platen size, the tapped hole pattern (thread size and spacing, from the press manual), clamp slot size, or magnetic platens.
• Minimum and maximum mold height and the opening stroke (or daylight).
• Locating ring: platen bore size (4.000 in is common in North America; the ring is made 3.990 in) and whether both platens use one.
• Nozzle radius and orifice, so the sprue bushing matches.
• Knockout pattern, rod size and thread, and whether the ejector is single or multi rod.
• Utilities: water thread (NPT in most North American plants), quick connect coupler brand, air and hydraulic core pull circuits.
• Robot and end of arm tooling: robot make, mounting and any EOAT TK must design for.

Running several presses? List the smallest and largest. See export molds for U.S. presses for how TK builds to North American press and plant standards.

These items do not change the steel, but they change the price and the schedule, and they are the most often missing from an RFQ.

• Required ship date or the date the mold must be running in your plant.
• Ship to address and Incoterms, so freight, duty and insurance are clear.
• Sample quantity at each trial and how samples ship.
• Approval level: dimensional report, FAI, PPAP, or validation for medical.
• Mold standards and documents: component brand, drawings, spare parts list, steel certificates.
• Trial attendance: in person, online, or samples only.
• NDA in place before files are shared.
• Start up support at your plant, if you need TK’s team on site.