Workholding is rarely the difficult half of a quotation. The difficult half is knowing what the tool has to do on your machine, in your cycle, against your gauge. A buyer who can hand over the part print, the machine data, the volume and the inspection method usually gets one price with no caveats; a buyer who can only give a shape gets a number that moves after the first trial cut.
The items below are the ones we ask for before we price a workholding or tooling job. If you can send them together, the quotation comes back with fewer assumptions and the price covers what you actually need.
Start with the part print, and say which dimensions matter
Send a drawing, not a sample alone. A sample tells us the shape; it does not tell us which faces are datum, how much stock you intend to leave, or which features are checked on incoming inspection. A STEP file is useful for geometry, but it carries no tolerance information, so pair it with a print or a marked-up sketch.
Mark the critical dimensions yourself. On most workholding jobs, a few dimensions control fit and the rest are reference. If we have to guess which ones you care about, we will hold tight tolerances everywhere, and you pay for that in machining time on faces that were never going to matter.
State your process as well as the part: milling, turning, grinding, EDM, welding, assembly, inspection. A fixture for a multi-axis machining centre and a fixture for a welding station look similar on paper and are built differently.
Give the machine, envelope, and tool-clearance constraints
Name the machine the tooling will sit on, with table size, T-slot or bolt pattern, travel, spindle or ram size, and, for presses, tonnage and shut height. A fixture that misses the table slots by a few millimetres gets modified after delivery, at both sides' cost.
Give the working envelope in all directions, including the space the tool needs, not only the space the part occupies. For automated cells add tool-changer, robot-gripper and sensor clearance. For manual load, tell us where the operator's hands have to go, and whether the part is loaded by one person or two.
Tell us what is already in the cell: existing pallets, tombstones, quick-changers, counterbores and datum holes on your table. Where we can reuse your interface, the build is cheaper and changeover on your side stays unchanged.
Specify the volume, the cycle time and the changeover you can accept
Annual quantity and the life you expect from the tool are different numbers, and both are needed. A fixture for a short low-volume run and one for continuous high-volume production differ in wear parts, clamping method, and how much hardening is worth doing. Say which you are buying for.
Give the cycle you must hit, and how long loading and unloading take today. Workholding is often where a cycle time is lost, because the part seats correctly but the clamp takes several seconds longer than the operation it supports. If there is a target, we design the actuator and the access to meet it.
Say whether the same fixture must hold several part numbers. Family tooling costs more to build and saves changeover time; the decision needs the part list and the difference between variants, so send those variants up front instead of one representative part.
Fix the lot size and the changeover your shop can actually run
High-mix, low-volume shops need quick-change fixtures, and quick change is a specification, not a wish. State the changeover time you can live with, and whether it must be done by one operator with hand tools or whether you have a setup person with a torque wrench and a gauge block.
List the parts that will run on this tooling over the next two years if you know them. The cost of designing for a known future part is small at the drawing stage and expensive after the first cut.
Where changeover is done by swapping a soft jaw or a nest rather than the whole base, say so. We design to that habit, because the fixture that stays on the table is the one your accuracy depends on.
Decide how the part is located and clamped
Tell us which features are already machined and reliable enough to locate against, and which faces are raw casting or saw-cut. Locating off a machined pad and clamping on the same pad is a decision made before the first machining operation, and it belongs in the request, not in a change order.
Give the clamping limit. For thin-wall parts, tell us how much force the part can take before it distorts, and which surfaces may be marked. Where a fixture is built to hold a part within tolerance and the part still moves under the cutter, the reason is usually here.
State what is available at the machine: compressed-air pressure and flow, hydraulic supply, or nothing at all. Manual clamp is a legitimate choice on low volume; it just has to be chosen, not discovered during commissioning.
Materials, coatings and the chips they leave behind
Send the material grade and condition, not only the generic family. Stainless, aluminium and cast iron behave differently under the same clamp, and swarf from each clears differently. If the part is scaled, oily or has a burr left from the previous process, say so; seating surfaces are the most common cause of a fixture that does not repeat.
Tell us how the fixture must handle coolant and chips: flush ports, wipers, raised pads, a purge on the locating pins. A fixture that has to be brushed clean between parts costs you seconds on every cycle.
Name any coating or surface finish on the part that must not be marked. That decides pad material, contact points, and whether we harden or replace consumables on a schedule.
Say who inspects the tool, and against what
Give the gauge, CMM, or go/no-go you will use to accept the parts, and where the CMM probes. A fixture designed against the shop's own check will pass; one designed against our check may not, if the two methods disagree.
State the accuracy you need the tooling to repeat, not only the accuracy you need the part to reach. Tooling tolerance is a fraction of part tolerance, and without the part number and its tolerance we cannot set it.
If you require a first-article report, a dimensional report on the fixture itself, or a documented setup sheet with the torque values and the order of clamping, ask for it in the request. It is priced work and it is cheaper to include than to add after an argument on the shop floor.
Maintenance, spares, and what you expect from us afterwards
Tell us who maintains the tooling and what records you keep. If your team replaces pins and pads, give us a drawing of those items and a part number of our own for them. If nobody on the floor can strip a fixture, the design should keep the wear parts on the outside.
List the spares you want delivered with the tool, and how fast a replacement must arrive. Consumables on the same lead time as the original build will stop the cell.
Tell us what happens when the part design changes: revision level, who issues it, and whether the tooling must be modified or rebuilt. It changes both the price and the drawings we keep on file.
Commercial details that should be settled in the request
Give the required delivery date, and say whether it is a prototype, a first production lot, or a repeat order. Prototype timing and production timing buy different amounts of engineering.
State how payment and revision work at your company: tooling paid once, amortised over volume, or re-quoted at each order. Say where design ownership sits, and who may release the drawing to a second source.
Name the acceptance point. A fixture signed off on your machine with your parts is a different handover from a fixture accepted in the supplier's shop against a gauge. We would rather agree which one you want than argue about it on the loading dock.
A short list to send with the enquiry
- Part print with critical dimensions marked, plus the STEP file
- Machine make and model, table interface, working envelope in every axis
- Annual quantity, tool life expected, cycle time and current load time
- Part numbers sharing the tooling, and the changeover time you accept
- Locating features, clamping-force limit, and available air, hydraulic or none
- Material grade and condition, coolant and chip handling, surfaces that must stay unmarked
- Inspection method, required repeatability, and the reports you want
- Maintenance owner, spares list, revision process, delivery date and acceptance point
That list fits on one page. A request that answers all of it usually gets one quotation with a clear price and no exclusions added later. A request that gives a drawing and a delivery date and nothing else gets a rough number, and the gap shows up as a change order after the first trial cut.
How PowerDe works with the information you send
PowerDe has built automation and non-standard equipment in Shenzhen since 2007, alongside production-line and process equipment, and workholding projects are scoped from customer drawings and process requirements rather than from a catalogue item. The same information set drives the internal review: the machine data sets the interface, the volume decides the wear parts, the inspection method decides what we measure before shipment.
Send the part print, the machine data and the volume, and we come back with the fixture or tooling approach we would build, the approach we would not recommend for your process, and the lead time behind it. Where the job needs design work rather than a build from your drawing, our engineering pages describe how that is scoped: engineering services, product development, hardware testing and non-standard automation equipment. Questions go to sales@powerde.net or +86 13023198376.
