Predictika · Custom manufacturing: injection molded part design checks against published guidelines

An AI sales agent's injection molding quote request, checked before it goes out

An AI sales agent prepares a quote request for a custom injection molded plastic part: the resin, the part size, wall thickness, draft angle, surface finish and any side core. Before it goes out, the agent sends it to Predictika, which checks it against a declarative model of Protolabs' published injection molding design guidelines and returns a verdict, every reason and the figures it computed.

Scope: Protolabs injection molding part design checks: size limits, wall thickness by resin, draft and finish, side-core undercuts, ribs and tolerance. See everything this validator covers

This validator models the published Protolabs plastic injection molding design guidelines for quote requests, not just the scenarios shown below.

  • Size — a maximum envelope of 18.9 x 29.6 x 8 in., a volume of 59 cu. in., a projected mold area of 175 sq. in., and a depth of 4 in. from the parting line (up to 8 in. if the parting line can pass through the middle of the part).
  • Wall thickness — the published range for ten resin families (ABS, acetal, acrylic, LCP, nylon, polycarbonate, polyester, polyethylene, PPS and polystyrene); the maximum wall stated on the request is compared with the published range.
  • Draft, finish, side cores and ribs — minimum draft of 0.5 degrees, 3 degrees for shut-off faces and PM-T1 textures, 5 degrees for PM-T2; side cores under 8.419 x 2.377 in. with a pull under 2.875 in.; ribs and bosses at 40 to 60 percent or more of the adjacent wall; a +/- 0.003 in. machining tolerance.

Any injection molding part request that touches these guidelines is in scope — not only the scenarios pictured here. Not covered: prices (Protolabs generates quotes from uploaded CAD and no public injection molding price list was found, so this validator produces no price build-up or line-item quote), lead times, mold types and ownership, liquid silicone molding, overmolding and insert molding, polypropylene wall thickness (two Protolabs pages show different minimums), and other Protolabs services.

The AI sales agentBuilds the injection molding quote request from the conversation and says it is ready.
Predictika validatorChecks every rule at once and returns the verdict, each finding, and the computed figures.

7 scenarios in 3 groups · each group runs from the agent’s first attempt to the outcome · click one to switch

What the agent proposes

The AI sales agent says

Illustrative agent statement. The validator receives the structured request below.

Proposing agent: AI sales agent (scripted)

Before sending, the agent must call Recorded run

Predictika validator


      

        
        
        
      

      
Waiting for the call.

      
    

  

  
  

    
Where rules-based CPQ gets it wrong
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Our assessment of what a typical rules-based CPQ (product rules, price rules and validation rules, as in Salesforce CPQ) does with the same cases. It is a judgment about effort and reliability, not a claim that nothing can be built.

    
What the validator caughtTypical rules-based CPQPredictika
Wall limits that depend on the resinOnly with care
Each resin has its own minimum and maximum wall, so ten resins need ten pairs of limits that must be kept in step with the guidelines.		The resin and the wall arrive together; the wall is checked against the range for the chosen resin on every call.
Draft that depends on finish and featuresOnly with workarounds
Draft needs depend on the texture chosen and on shut-off faces; a product rule has to combine two or three inputs and a quote can break several at once.		Draft, finish and shut-off faces are checked together on every call and every shortfall is reported in one answer.
Size, volume and depth limits that interactOnly with care
Depth depends on whether the parting line can pass through the middle of the part, so one limit changes with another input.		The depth limit is applied with the parting-line input on every call, whichever order they arrive in.
Stated figure that must match the guidelinesOnly with care
A stated maximum wall is a free-entry field; a rule can compare it with the published range, but someone has to write and maintain that comparison.		The stated maximum wall travels with the request and is compared with the resin range on every call.
Every problem returned in one answerOnly with workarounds
Rules tend to fire as the order is saved or a step is completed, so a rep often fixes one error and meets the next.		All findings come back together, whatever order the choices arrived in.

  

  

    
What this validator catches: findings from its test cases
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Every rule is checked on every call, in any order the choices arrive; one problem never hides another. Blocking findings stop the quote; approval findings need a person to sign off; everything else is computed.

    
1The wall is 0.029 in. thick; this resin needs at least 0.03 in.
2The wall is 0.116 in. thick; this resin allows at most 0.115 in.
3The wall is 0.044 in. thick; this resin needs at least 0.045 in.
4The wall is 0.141 in. thick; this resin allows at most 0.14 in.
5The wall is 0.501 in. thick; this resin allows at most 0.5 in.
6The wall is 0.034 in. thick; this resin needs at least 0.035 in.
7The quote states a maximum wall of 0.15 in. for this resin; the published range tops out at 0.14 in.
8The longest dimension is 29.7 in.; the limit is 29.6 in.
9The middle dimension is 19.0 in.; the limit is 18.9 in.
10The shortest dimension is 8.1 in.; the limit is 8 in.
11The part volume is 60.0 cu. in.; the limit is 59 cu. in.
12The projected mold area is 176.0 sq. in.; the limit is 175 sq. in.
13The depth is 4.5 in. from the parting line; the limit is 4 in. unless the parting line can pass through the middle of the part.
14The depth is 8.5 in.; the limit is 8 in., and only when the parting line can pass through the middle of the part.
15The draft angle is 0.5 degrees; Protolabs recommends 2 degrees in most situations, so a person should confirm.
16The draft angle is 0.4 degrees; even vertical faces need at least 0.5 degrees.
17Shut-off faces need at least 3 degrees of draft; the part has 2.9.
18A PM-T1 light texture needs at least 3 degrees of draft; the part has 2.9.
19A PM-T2 medium texture needs at least 5 degrees of draft; the part has 4.9.
20The side core is 8.419 in. wide; it must be less than 8.419 in.
21The side core is 2.377 in. high; it must be less than 2.377 in.
22The side core pull is 2.875 in.; it must be less than 2.875 in.
23The quote asks for a tolerance of +/- 0.002 in.; the standard machining tolerance is +/- 0.003 in.
24Ribs and bosses are 50 percent of the adjacent wall; the guideline is 40 to 60 percent or more, so a person should confirm.
25Ribs and bosses are 39 percent of the adjacent wall; they should be no less than 40 to 60 percent.
26The longest dimension is 31.0 in.; the limit is 29.6 in.
27The part volume is 70.0 cu. in.; the limit is 59 cu. in.
28The wall is 0.2 in. thick; this resin allows at most 0.115 in.
29A PM-T2 medium texture needs at least 5 degrees of draft; the part has 1.0.
30Ribs and bosses are 30 percent of the adjacent wall; they should be no less than 40 to 60 percent.
31The draft angle is 1.0 degrees; Protolabs recommends 2 degrees in most situations, so a person should confirm.

  

  

    
Scenarios and results
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The recorded result of the validator for each scenario on this page: the request the AI agent sent, the verdict, and every finding, in the order they appear above.

    
1. Wall and draft: A polycarbonate part with a thin wall and a medium texture on little draft

    
The agent's request. Please quote an injection molded polycarbonate part, 9 x 6 x 2.5 in., 12 cu. in. in volume with a 40 sq. in. projected area and a depth of 2 in., with a 0.03 in. wall, 1 degree of draft and a PM-T2 finish, ribs at 60 percent of the wall and a tolerance of +/- 0.005 in. The quote states a maximum wall of 0.15 in. for this resin. It is ready to send.

    
Verdict: Blocked.

    
    
      
  • Wall thinner than the resin range. The wall is 0.03 in. thick; this resin needs at least 0.04 in.
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  • Draft too small for a medium texture (PM-T2). A PM-T2 medium texture needs at least 5 degrees of draft; the part has 1.0.
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  • Draft below the usual 2 degrees. The draft angle is 1.0 degrees; Protolabs recommends 2 degrees in most situations, so a person should confirm.
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2. Wall and draft: The agent resubmits after fixing the errors

    
The agent's request. Please quote an injection molded polycarbonate part, 9 x 6 x 2.5 in., 12 cu. in. in volume with a 40 sq. in. projected area and a depth of 2 in., with a 0.06 in. wall, 5 degrees of draft and a PM-T2 finish, ribs at 60 percent of the wall and a tolerance of +/- 0.005 in. The quote states a maximum wall of 0.15 in. for this resin. It is ready to send.

    
Verdict: Allowed.

    
    
      
  • Part summary. Wall range for this resin 0.04 to 0.15 in., draft 5.0 degrees.
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3. Size and depth: An oversize ABS part, 5 in. deep with no through-middle parting line

    
The agent's request. Please quote an injection molded ABS part, 31 x 17 x 6 in., 70 cu. in. in volume with a 150 sq. in. projected area and a depth of 5 in., with a 0.1 in. wall, 2.5 degrees of draft and a SPI-B1 finish, ribs at 60 percent of the wall and a tolerance of +/- 0.005 in. The quote states a maximum wall of 0.14 in. for this resin. It is ready to send.

    
Verdict: Blocked.

    
    
      
  • Part longer than the size limit. The longest dimension is 31.0 in.; the limit is 29.6 in.
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  • Part volume over the limit. The part volume is 70.0 cu. in.; the limit is 59 cu. in.
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  • Depth over 4 in. from the parting line. The depth is 5.0 in. from the parting line; the limit is 4 in. unless the parting line can pass through the middle of the part.
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4. Size and depth: The agent resubmits after fixing the errors

    
The agent's request. Please quote an injection molded ABS part, 24 x 15 x 6 in., 50 cu. in. in volume with a 150 sq. in. projected area and a depth of 6 in. with the parting line through the middle of the part, with a 0.1 in. wall, 2.5 degrees of draft and a SPI-B1 finish, ribs at 60 percent of the wall and a tolerance of +/- 0.005 in. The quote states a maximum wall of 0.14 in. for this resin. It is ready to send.

    
Verdict: Allowed.

    
    
      
  • Part summary. Wall range for this resin 0.045 to 0.14 in., draft 2.5 degrees.
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5. Side core, shut-off and ribs: A nylon part with a long side core, shut-off faces and thin ribs

    
The agent's request. Please quote an injection molded nylon part, 10 x 7 x 3 in., 14 cu. in. in volume with a 45 sq. in. projected area and a depth of 2.5 in., with a 0.08 in. wall, 2 degrees of draft and a PM-F1 finish, shut-off faces, and a side core 3 in. wide, 1 in. high with a 3.1 in. pull, ribs at 35 percent of the wall and a tolerance of +/- 0.005 in. The quote states a maximum wall of 0.115 in. for this resin. It is ready to send.

    
Verdict: Blocked.

    
    
      
  • Draft too small for shut-off faces. Shut-off faces need at least 3 degrees of draft; the part has 2.0.
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  • Side core pull too long. The side core pull is 3.1 in.; it must be less than 2.875 in.
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  • Rib or boss too thin for its wall. Ribs and bosses are 35 percent of the adjacent wall; they should be no less than 40 to 60 percent.
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6. Side core, shut-off and ribs: The agent resubmits after fixing the errors

    
The agent's request. Please quote an injection molded nylon part, 10 x 7 x 3 in., 14 cu. in. in volume with a 45 sq. in. projected area and a depth of 2.5 in., with a 0.08 in. wall, 3 degrees of draft and a PM-F1 finish, shut-off faces, and a side core 3 in. wide, 1 in. high with a 2.5 in. pull, ribs at 50 percent of the wall and a tolerance of +/- 0.005 in. The quote states a maximum wall of 0.115 in. for this resin. It is ready to send.

    
Verdict: Needs approval.

    
    
      
  • Rib or boss thin for its wall. Ribs and bosses are 50 percent of the adjacent wall; the guideline is 40 to 60 percent or more, so a person should confirm.
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  • Part summary. Wall range for this resin 0.03 to 0.115 in., draft 3.0 degrees.
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7. Side core, shut-off and ribs: The agent resubmits after fixing the errors

    
The agent's request. Please quote an injection molded nylon part, 10 x 7 x 3 in., 14 cu. in. in volume with a 45 sq. in. projected area and a depth of 2.5 in., with a 0.08 in. wall, 3 degrees of draft and a PM-F1 finish, shut-off faces, and a side core 3 in. wide, 1 in. high with a 2.5 in. pull, ribs at 60 percent of the wall and a tolerance of +/- 0.005 in. The quote states a maximum wall of 0.115 in. for this resin. It is ready to send.

    
Verdict: Allowed.

    
    
      
  • Part summary. Wall range for this resin 0.03 to 0.115 in., draft 3.0 degrees.
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Narration transcript
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The text of the narrated walkthrough, step by step.

    
    
      
  1. Welcome to a demo of Predictika's Validator. An AI sales agent prepares a quote request for a custom injection molded plastic part: the resin, the part size, wall thickness, and more. Before it goes out, the agent sends it to Predictika, which checks it against a declarative model of Protolabs' published injection molding design guidelines and returns a verdict, every reason and the figures it computed.
    2. 
      
  2. I will start with the first request by the agent.
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  3. The agent says. Please quote an injection molded nylon part, 10 x 7 x 3 in., 14 cu. in. in volume with a 45 sq. in. projected area and a depth of 2.5 in.. The quote states a maximum wall of 0.115 in. for this resin. The rest of the request is on screen.
    4. 
      
  4. Before it goes out, the agent calls the validator.
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  5. Blocked, with three findings, all in one answer. Shut-off faces need at least 3 degrees of draft; the part has 2.0. The side core pull is 3.1 in.; it must be less than 2.875 in. Ribs and bosses are 35 percent of the adjacent wall; they should be no less than 40 to 60 percent.
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  6. The validator returned three blocking findings in one answer. A check that reads one field at a time would pass most of this; it shows only when the choices in the quote are checked against each other.
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  7. What this shows: for wall limits that depend on the resin, a rules-based CPQ is error-prone for this.
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  8. Now the agent resubmits.
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  9. The corrected request. It changes the draft angle to 3 degrees, the rib thickness to 50 and the side core pull to 2.5.
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  10. It calls the validator again.
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  11. Not blocked, but held for a person.
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  12. The three blocking findings are cleared; one approval remains for a person: rib or boss thin for its wall.
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  13. The agent resubmits once more.
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  14. The revised request. It changes the rib thickness to 60.
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  15. It calls the validator once more.
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  16. This time the validator clears it.
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  17. The earlier finding is cleared, and the validator's figure matches the quote.
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  18. Three problems caught in one call, fixed in two passes, and a clean quote. That is the value of Predictika's validator: catching mistakes before they reach the customer. Now you can try the other scenarios yourself.
    19.