2026-09-21 · KeXinMaterials 編集チーム

カスタムフォーム設計 保護ケース B2B ガイド: CNC vs Pick-and-Pluck vs パッドディバイダー

ケースは目に見える部分です。機材を守るかを決めるのはフォームです。Pelican はオンラインフォーム設計ツールを提供しますが、 Dudeの直工場の多くは持っていません。KeXinMaterials（box-beeaa.com）はご指定の機材リストに基づき CNC・水射流・レーザーでフォームを裁断します。設計ごとの型代なし、サンプル 7-15日、無料修正 2回、MOQ 100 個、生産 30-45日。2026 調達ガイド。

The Four Interior Types and When Each One Is Right

Pick-and-pluck, padded divider, egg-crate, and CNC cut are not quality tiers. They are four different answers to four different questions about what you are protecting and who will open the case.

Pick-and-pluck (P&P): solid layers of closed-cell foam the end user trims to fit with a foam knife. Cheap, no design required, and genuinely flexible — a distributor carrying a broad catalogue of unknown equipment can ship one case and let the end user adapt it. Its weakness is precision: the user cuts a rectangle and a hole, and the fit is only as good as their cut. Best for 10-100 unit builds, prototypes, and cases whose contents change.

Padded divider: sheets of closed-cell PE foam in a cut pattern, held in place with hook-and-loop tape. Fast to change, no cutting, good for accessories that come and go. The weakness is vertical crush — a divider protects against abrasion and light impact, not against a 1 m drop onto a lens. Best for camera bodies, audio gear, and accessory-heavy kits.

Egg-crate (convoluted) foam lid: alternating peaks and valleys in the lid, usually open or closed cell. It cradles irregular shapes and distributes contact across a wider area. Commonly used as a lid layer above a P&P or CNC base. The weakness is that it consumes a lot of vertical space for little protection, so it is a lid solution, not a base solution.

CNC cut (or waterjet / laser cut): precision cutouts for the exact footprint of each item, including cable pass-throughs, dedicated battery bays, lens cradles, and printed index labels. No tooling die — the cut path is data. The weakness is that the design is fixed at production time, so a content change means a re-cut. Best for 100+ MOQ with a stable equipment list.

The decision rule: if the contents are unknown or change per shipment, use P&P. If the contents are known but the arrangement is flexible, use padded dividers. If the contents are known, fixed, and valuable, use CNC cut. If the case is opened frequently in the field and needs a soft top surface, add an egg-crate lid layer over a CNC base.

B2B cost positioning (2026, FOB Shenzhen/Ningbo, 100+ MOQ): P&P interior included at the base case price. Padded divider adds USD 3-8/unit. Egg-crate lid layer adds USD 4-10/unit. CNC-cut layered interior adds USD 10-25/unit. Above those, a custom foam insert is a design conversation, not a price-list item.

Foam Material and Density Selection

Getting the density right is what separates a case that protects from a case that only fits. Density, not thickness, is the primary variable.

Closed-cell polyethylene (PE / cross-linked PE): the default for hard protective cases. Water-resistant, chemically inert, does not absorb moisture, and holds its shape. Densities 25-35 lb/ft3 (0.42-0.59 g/cm3) give structural protection against 1-2 m drops. This is what most B2B protective cases use for the base layer.

Polyurethane (PU) foam: density 15-20 lb/ft3 (0.25-0.34 g/cm3). Softer, better energy absorption at low stress, used for delicate items — optics, gimbals, sensors, calibrated instruments. Most PU is open-cell and absorbs water, so it belongs in the lid or in a removable layer, not in the base of a waterproof case.

EVA foam: density 30-45 lb/ft3. Lightweight with decent shock absorption, common in low-cost and foam-moulded products. Less durable under repeated compression than PE and degrades faster. Acceptable for light electronics; not the choice for a case that will be reused for years.

Density selection rule: hard, dense, and heavy items go in higher density foam (30-35 lb/ft3) because they need resistance to deformation. Delicate, sensitive, and light items go in lower density foam (15-20 lb/ft3) because they need energy absorption, not stiffness. Getting this backwards is the most common custom foam mistake.

Thickness: 25-30 mm for 15-20 lb/ft3 PU; 40-50 mm for 25-35 lb/ft3 PE. Thicker foam does not linearly increase protection — once the item is fully surrounded, additional thickness adds dead volume and weight. The optimum is roughly 1.5x to 2x the item dimension in the direction of drop load.

Layering: the best interiors are layered. A dense PE base for the heavy items and battery bays, a softer PU layer in the lid for the gimbal or optics, and a thin egg-crate surface layer where items contact the lid when closed. This is the standard construction for camera, drone, and survey kits.

Fire performance: PE foam typically meets FMVSS 302 and CA TB 117. PU foam varies — specify the requirement explicitly if the case will travel by air or in enclosed vehicles, and get the compliance statement in writing.

Anti-static: for electronics and defence/aerospace equipment, specify anti-static (dissipative) foam meeting IEC 61340 classifications. This is a real requirement, not a preference, and it should be on the equipment list from the first RFQ rather than added after a static damage incident.

B2B relevance: the foam specification should be as detailed as the case specification. "Custom foam" is not a specification. "35 lb/ft3 closed-cell PE base, 25 mm 20 lb/ft3 PU lid layer, anti-static to IEC 61340, egg-crate surface layer" is a specification a factory can quote against and a buyer can verify.

Preparing an Equipment List That Cuts Cleanly the First Time

The single biggest determinant of sample revision count is the quality of the equipment list the buyer supplies. Most two-round revision budgets are spent fixing information the buyer could have provided.

What the factory needs per item: name, quantity, longest dimension (L), width (W), height (H) in mm, weight in kg, and whether the item is fragile. Photos from a fixed distance with a ruler in frame are worth more than a written description and cost the buyer five minutes.

Item 1 — dimensions should be the dimensions that matter, not the shipping carton dimensions. A camera lens is specified by its maximum diameter, not by the length of the retail box it came in. A drone is specified folded, with the propellers removed. A battery is specified by its cell dimensions, not by the charger packaging.

Item 2 — declare protrusions. Antennae, handles, cables, connectors, and mounting brackets are the parts that determine whether an item actually fits its cutout. A cutout sized to the body alone will not accept the item if it has a 40 mm antenna.

Item 3 — declare consumables and spares. Battery count, spare propellers, filter sets, spare cables, and a spare controller should all be listed with quantities, because they determine the volume budget. The most common cause of a failed first sample is the buyer under-counting accessories by 30-40%.

Item 4 — declare the access path. If an item has a connector that must be reachable without removing it from the case — a charging port, a data connector, a display — say so. The cutout is designed around the access, not just the footprint.

Item 5 — declare the closure behaviour. If two items must sit face to face when the case is closed, they need a divider or a spacing allowance. If an item must be reachable quickly, it goes in the top layer.

Layout convention: the base layer holds the heavy items and the batteries; the lid layer holds controllers, accessories, and soft items. This is the standard convention and it makes the case usable in the field, not just protective in transit. Declaring it removes a whole round of revision.

Cable management: declare cable lengths and routing. A long tether that must reach from the base to the lid needs a pass-through cutout sized to the cable loop in its relaxed state, not its taut state.

B2B relevance: a buyer who supplies a complete equipment list on the first RFQ typically approves a sample in one round instead of two, which saves roughly 7 days on a 30-45 day production schedule. On a programme with a fixed launch date, that week is often the difference between hitting and missing it.

The Design Workflow, Cost, and Turnaround

Six steps from equipment list to production run, with the realistic duration and cost at each step so the buyer can plan a launch date.

Step 1 — Specification (buyer, 1-3 days): submit the equipment list, target case internal dimensions, carriage class (check-in or cabin), IP requirement, and any compliance requirement. No tooling cost, no commitment.

Step 2 — Cut path design (KeXinMaterials, 1-2 days): the cut path is produced from the equipment list or from a 3D scan of the physical equipment. The buyer receives a 2D layout drawing for review. This is the first opportunity to catch a layout error cheaply, and it is worth reviewing carefully rather than approving reflexively.

Step 3 — Sample (7-15 days): one to two sample cases are produced with the custom foam. The buyer physically fits every item and confirms the cutouts. Two adjustment rounds are included.

Step 4 — Approval and freeze (1 day): the buyer signs off. The cut path is frozen. Changes after this point are a new sample, not a revision.

Step 5 — Production (30-45 days total for a 100+ MOQ run): case moulding 15-20 days, foam CNC 7-10 days, assembly and QC 5-8 days. Runs concurrently where the dependency allows.

Step 6 — QC (within the above): 100% fit check on the first 10 units of the run, then AQL sampling per ISO 2859-1. Drop test verification per MIL-STD-810 method reference where specified.

Cost: no per-design tooling charge for CNC, waterjet, or laser cutting — the cost is material, not a die. This is the structural difference from a moulded or vacuum-formed interior, where a new equipment list means a new tool and often a USD 2,000-10,000 charge. For a product that will be produced in multiple runs over its life, CNC is dramatically cheaper than tooling.

Interior cost adders (2026, 100+ MOQ FOB Shenzhen/Ningbo): P&P included. Padded divider USD 3-8/unit. Egg-crate lid layer USD 4-10/unit. CNC-cut layered interior USD 10-25/unit. Anti-static foam and certifiable fire performance are quoted per specification.

MOQ and commercial terms: 100 units per model per interior design; 50-100 units for standard interiors. T/T 30% deposit + 70% before shipment. EXW Shenzhen / FOB Shenzhen / FOB Ningbo only. KeXinMaterials is B2B export only — no retail channel, no DDP quotation, and no overseas warehouse, so duty, clearance, and inland distribution are handled by the buyer.

B2B recommendation: freeze the equipment list before the first sample, not after it. The revision rounds exist for layout judgement (does the user prefer the controller in the lid or the base), not for missing information. Buyers who use them that way pay for the sample cycle twice.

よくある質問

関連記事

• Foam Interior: Pick-and-Pluck vs CNC vs EVA B2B Comparison
• Protective Case Foam Interior Options
• Custom Foam Insert Case Design Guide
• Case Customization: Logo, Color, Foam, Hardware B2B Guide
• OEM Protective Case MOQs and Lead Times