A PET preform injection molding machine is bought to stop paying a supplier for preforms. Machine size follows daily preform demand, mold cost and connected load, not clamping tonnage
A 300 BPH five gallon filling line fills 2,400 bottles in an eight hour shift, so it needs 2,400 PET preforms.
The MG-628PET makes 90 preforms an hour, or 2,160 over twenty four hours. One machine cannot cover a single shift on that line.
Two machines cover it, or run the blow molding machine and filler below 270 BPH.
Preforms store, so a two day buffer lets injection run unattended overnight.
The Preform Mold Is Not in the Machine Price
Injection molding machines ship without a mold. The preform mold is quoted separately by cavity count, steel grade and hot runner.
A 750 g five gallon preform starts at two cavities. Four cavities need the 100 mm screw on the MG-628PET.
Neck finish makes each mold single purpose. A 55 mm five gallon opening will not run a 28 mm PCO water bottle, so every new bottle size is a second mold.
Power, Weight and Floor Space
Pump motor and heater draw 63 kW on the MG-398PET and 97 kW on the MG-628PET, with a 15 HP or 25 HP chiller on top.
Send both figures to your electrician and the weight to whoever built the slab, before the order. Cable size, transformer capacity and floor loading cannot change later.
Tie bar spacing caps mold outline at 720 by 720 mm, and mold height runs 280 to 800 mm on the smaller machine.
| What it decides | MG-398PET | MG-628PET |
|---|---|---|
| Preforms per hour, 750 g | 50 | 90 |
| Preforms per day, running 24 hours | 1,200 | 2,160 |
| Connected load, pump and heater | 63 kW | 97 kW |
| Chiller supplied | 15 HP | 25 HP |
| Machine weight | 15.7 t | 31 t |
| Tie bar spacing | 720 × 720 mm | 850 × 850 mm |
| Mold height range | 280 to 800 mm | 350 to 900 mm |
| Cavities on a 750 g mold | 2 | 4 |
| Hopper dryer | 300 kg | 400 kg |
Chiller, hopper dryer, auto loader and mold temperature controller are quoted outside the injection unit.
Full preform injection molding machine specifications sit on the product page.
Will the Quoted Output Survive a Real Mold
Quoted output comes from a dry run on the supplier’s mold. Yours depends on your cooling water, room temperature and a 750 g wall that holds heat.
Ask for a trial on your preform drawing and count parts over one hour, not one cycle.
If output falls after six hours, the cause is cooling, not tonnage.
Make Preforms or Buy Them
One MG-628PET running around the clock makes about 648,000 preforms a year over 300 working days, or 486 tonnes of PET at 750 g each.
Below that, mold, dryer and startup rejects are spread over fewer bottles, and bought preforms usually cost less.
Above it, in-house injection removes preform lead time and the freight on empty preforms, which take several times the truck space of the bottles they become.
Buy preforms while the mold is being made, then move volume across once trial output holds.
Frequently Asked Questions
How many injection molding machines does a 300 BPH line need?
Two MG-628PET units, or one if the filler runs below 270 BPH. A single machine at 90 preforms an hour cannot supply 2,400 a day.
Is the preform mold included in the machine price?
No. Machines ship without a mold, and the preform mold is quoted by cavity count, steel grade and hot runner.
How much power does a preform injection molding machine need?
63 kW on the MG-398PET and 97 kW on the MG-628PET, pump and heater together, plus a 15 HP or 25 HP chiller.
Can one machine make both preforms and bottle caps?
Yes, with a different mold and screw, but the cycle and cooling differ. Count the changeover time before sharing one machine with bottle caps.
Send the bottle size, preform weight and daily target. JNDWATER replies with machine size, cavity count and the auxiliary list. More models sit under injection molding machines.
