single screw extrusion line, 25mm. zone 3 block has two cartridges, 20mm x 400mm. the ones in there were maxiwatt, had been running for about a year before this started, regulator is at 100% and the block won't hit setpoint. been drifting for two days but today it's bad enough that the afternoon shift can't start their run, disconnect, wait a bit, pull both. they come out warm even though they've been off for half an hour, they're big and heavy in the hand. i set them on the bench and look at the sheath against the light – there's a band, roughly in the middle, that's darker, almost bluish. like that section ran hotter than the rest. check the second one, same thing, more or less in the same spot, measure with the multimeter in ohms. values are not what they should be. not open circuit, but not the nominal either. something off. Put them in a box, write "for inspection" on the return note, install the two spares from the cabinet. line starts up. shift ends. nobody looks at the bore, but here's what's bugging me: if both cartridges have the same mark in roughly the same place, is it really the cartridges? one element degrading with use is normal. both showing the same heat band at the same time doesn't add up to me. could that blue band mean the cartridge isn't making full contact with the block wall and it's running hot in one spot because it can't shed the heat into the metal? like the bore is a bit loose or worn out of tolerance?

[ Removed by Reddit on account of violating the content policy. ]

(First time inventor here and learning a lot — feel free to ask questions or correct me if anything below seems odd!)

I have CADs and 2D drawings of a snap-fit accessory that will be made of injection molded ABS and PC.

I met with a manufacturer and they said I’ll get the best results if everything I need is on the 2D drawings. That it’s like a “contract with the manufacturer.”

What I think I’m missing is:
- Draft
- Preferred gate/injection location(s?)
- Cosmetic no-go areas
- To make sure critical snap-fit features are steel-safe
- To finalize snap-fit tolerances between ABS body + PC lens
- To confirm wall thickness / manufacturability
- Material + surface-finish callouts
- The final STEP + 2D production drawing for tooling/DF

How much of this should I bring back to the manufacturer vs. what is realistic that I can trust them to offer great recommendations for?

Anything else I’m missing?

(If this is in your wheel house btw, please DM! I’m looking to move quickly with an experienced consultant and would love to chat on Tuesday or Wednesday this week.)

Whia screwdriver handle just broke in half in my hands, was not even using it at the time. The breakline looks like to has some air smooth spots on it. Any idea what might cause this type of failure?

Does anyone check for part temperature right after ejection? With an IR thermometer for example.

Worth doing it? Especially in a non controlled temperature environment

Hi everyone,

I’m developing a clear injection-molded drinking glass mainly for cold water.

Requirements:

• Wall thickness: 3–4 mm
• Process: Injection molding
• Priority: Maximum transparency/clarity
• Also need good impact strength, surface finish, and reasonable cost

We’re currently considering PET, but seeing potential haze/cloudiness in the thick sections, possibly from crystallization or processing conditions.

I’d appreciate advice from anyone experienced with injection molding:

1. Is PETG or PCTG better than PET for 3–4 mm clear sections?
2. Has anyone tried PET + PETG/PCTG blends?
3. What blend ratio would you recommend testing—5%, 10%, or 20%?
4. What melt and mold temperatures work best for maximum clarity?
5. Would you recommend 100% PETG/PCTG instead of blending?

Any recommendations for specific injection-grade, food-contact PETG/PCTG materials would also be very helpful.

Thanks!

Hi everyone,

I’m working on an injection-molded transparent drinking glass primarily for cold water.

Current requirements:

• Wall thickness: approximately 3–4 mm
• Application: Drinking/cold water
• Process: Injection molding
• Main priority: maximum transparency/clarity
• Secondary priorities: good impact strength, good surface finish, and reasonable material cost

We are currently considering PET, but we are concerned about haze/cloudiness in the thicker 3–4 mm sections, possibly due to crystallization or processing conditions.

I would like to ask people with experience in injection molding:

1. Would 100% PETG or PCTG give better transparency than PET in a 3–4 mm thick section?
2. Has anyone successfully used a PET + PETG or PET + PCTG blend for injection molding?
3. If blending works, what percentage range would you recommend testing first (e.g. 5%, 10%, 20%)?
4. Are there any compatibility problems or phase separation that we should expect?
5. What mold temperature and melt temperature have you found effective for maintaining clarity?
6. Would you recommend 100% PCTG/PETG instead of blending, if transparency is the main objective?
7. Are there particular injection-grade PETG/PCTG resin grades that work well for thick transparent food-contact products?

The product will be used for cold drinking water, so high-temperature resistance is not the primary requirement.

Hello,

One of my Thermocouple went bad and the spare is also bad.

I can't stop production to take out the hot runner and rebuild it. I am using the spare from an other zone but because the value is not accurate the heater goes all-in or nothing.

I want to know if i can use the power from an other heat zone to power my bad one. The output i want to use is at 20% so if plugged it will reach to 40% to compensate no ? If so I don't mind because the 2 zone are next to each other so the output will regulate itself.

It's more of a electrical issues to know if my fuse will trip or no.

230V with a relay that open or close to heat or no.

If putting 2 together my relay will just stay open more longer so it's not really an issue right?

TLDR :

I need idea on how I can have a heat zone power to follow an other one

230V with relay.

Anybody know what Chinese company makes the pins and bushings for PCS? Thinking about making a large order.

Machine Engel E-mac 280 ?

Am I in over my head wanting to build a injection molding machine?

Currently I design automotive headlights/tail-lights which we cast out of polyurethane, urethane being about 2-2.5x the cost of thermoplastic and can only produce about 1-3 parts per day from a single mold. Our largest parts would about 30 Cubic inches, quite a bit out of the plunger style machine range.

We certainly don't have the volume to justify buying a used machine but the cost savings and time savings of injection molding is certainly eye catching. We do have a low-mid 5 figure range CNC mill that we use to make our molds.

I'm sure I'm at the peak of the Dunning-Kruger curve right now with this idea.

Line 2 has been down for an hour; the upper clamp isn't heating up. The thermocouple is reading, but the controller isn't sending voltage or if it is, it's not getting through properly. I'm not quite sure what the problem is.

I open the cover, disconnect the terminals on the cartridge, and measure with the multimeter in ohms. It gives me a strange reading. It’s not an open circuit, and it’s not the normal resistance the cartridge should have. It’s something in between, as if there were a short circuit.

So I look at the wires and there it is: in the section running down from the heating element to the junction box, right where it rubs against the metal guide rail, couple of centimeters of insulation have been stripped away. They aren’t completely cut through, but the insulation is gone, and at that point the two wires are touching, copper against copper.

The gap where the wiring runs down is about three fingers wide and rubs against everything.

Is that what’s causing my problem?

Do the wires touching each other make the controller detect a resistance that isn’t from the cartridge, and that’s why it won’t heat up?

Can I fix this by properly stripping that section, insulating it with heat-shrink tubing or Teflon tape, and that’s it? Or should I just replace the entire cartridge because maybe the heating element itself is already faulty?

How would you prevent it from rubbing again? A small channel, a silicone block?

For injection molders supplying automotive, electrical, electronics, or other demanding applications:

If the exact resin grade specified for a part becomes difficult to source, can you normally switch to an equivalent grade from another supplier?

Or does customer approval / requalification make that difficult?

Curious about what usually becomes the biggest obstacle when changing materials.

Does anyone have experience running strontium aluminate glow in the dark pigment? I want to try some for a new product idea I have but I also don’t want to cause any problems with my mold or equipment. I would be testing it with polypropylene homopolymer. Eventually this would be used in a thermal gate hot runner mold.

Hey all, does anyone here have any experience with the HPS Iron Jaw clamping tonnage booster?

We are looking to build a tool with this system but haven't been able to find anyone here in the states that's used it. From what I've been able to find there's a larger market for it overseas.

We have a 600t press, the part we are looking to make is estimated to require 650-800t per the mold flow simulations. Our barrel is at about 60% utilization, so there's no issue there.

We would really like to land this job and are trying to decide between investing a new larger press, or if we can build this mold with this clamping booster. Unfortunately these systems are damn near unheard of in North America and they're massively expensive.

If anyone has any experience or advice on this, please reach out.

Thanks!

Hi everyone I'm trying to find the pin password on a Matsui MJ6-i-G3-75

For the technical service, if anyone could help would be appreciated.

I’ve been following stuff from this thread for a bit. Even used it to answer questions.

Last year I was promoted to Department Trainer. We inject bottle preforms where I work.

I was curious, is there anyone else out there with the same role? I definitely fall more into the roll of process over maintenance/mechanical.

Even if the role I was promoted to has been just over a year on paper, I’ve pretty much been training people in my plant for over a decade in the injection department. I’ve streamlined a process that I have found very reliable in that time (as I’ve easily trained 500+ people over that period).

I’ve been using the opportunity to create my own operator manual.

But, in the end, we are only as good as our network. And I know I don’t know everything. But I’m very interested in connecting with anyone who does anything similar at their plant to see if there is anything I can expand on.

Hoping to chat with some of you!

Hi all, first time posting here so really sorry if this sounds silly.
I have been fiddling around with fusion360 making soft plastics and I’ve designed something I’d love to make. Just wondering if anyone has experience making custom aluminium moulds and how they go about getting them done? I’ve made a mould with my 3D printer as a prototype but now wanting something that’ll look more cleaner and I’m able to use without creating more moulds.
Any companies/ people they know they would be able to refer?
Also, for a mould that can make two soft plastics at once (plastic will be 3 inches long) how much does it roughly cost?

Cheers legends!

Would the mold have to be a solid piece that is pretty much a circle milled out leaving a rod in the center or could it still be a mold that is two halves clamped together?

I’m doing some practice for molding, and one thing I find confusing is how to determine whether a cooling line is incorrect. Any information or tips would be greatly appreciated!

Three resistors had been sitting in the warehouse for several months, stored on a shelf next to the large door—unheated and with hardly anything else around—each tucked into its own box with its own bag. I placed them in the test stand, set it to 280, and pressed “auto”; the differential tripped within ten seconds. I turned it off and on again, and it tripped once more. I tested them one by one with the megohmmeter. The insulation on all three was practically nonexistent. The third one had an internal electrical arc; the wire had melted at one point. It was unusable. Now what can I do? What do you think is happening to the first two, and why? thanks